FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsserver/nfs_nfsdstate.c

     /*-
      * Copyright (c) 2009 Rick Macklem, University of Guelph
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/10.0/sys/fs/nfsserver/nfs_nfsdstate.c 245909 2013-01-25 15:25:24Z jhb $");
    
    #ifndef APPLEKEXT
    #include <fs/nfs/nfsport.h>
    
    struct nfsrv_stablefirst nfsrv_stablefirst;
    int nfsrv_issuedelegs = 0;
    int nfsrv_dolocallocks = 0;
    struct nfsv4lock nfsv4rootfs_lock;
    
    extern int newnfs_numnfsd;
    extern struct nfsstats newnfsstats;
    extern int nfsrv_lease;
    extern struct timeval nfsboottime;
    extern u_int32_t newnfs_true, newnfs_false;
    NFSV4ROOTLOCKMUTEX;
    NFSSTATESPINLOCK;
    
    /*
     * Hash lists for nfs V4.
     * (Some would put them in the .h file, but I don't like declaring storage
     *  in a .h)
     */
    struct nfsclienthashhead nfsclienthash[NFSCLIENTHASHSIZE];
    struct nfslockhashhead nfslockhash[NFSLOCKHASHSIZE];
    #endif  /* !APPLEKEXT */
    
    static u_int32_t nfsrv_openpluslock = 0, nfsrv_delegatecnt = 0;
    static time_t nfsrvboottime;
    static int nfsrv_writedelegifpos = 1;
    static int nfsrv_returnoldstateid = 0, nfsrv_clients = 0;
    static int nfsrv_clienthighwater = NFSRV_CLIENTHIGHWATER;
    static int nfsrv_nogsscallback = 0;
    
    /* local functions */
    static void nfsrv_dumpaclient(struct nfsclient *clp,
        struct nfsd_dumpclients *dumpp);
    static void nfsrv_freeopenowner(struct nfsstate *stp, int cansleep,
        NFSPROC_T *p);
    static int nfsrv_freeopen(struct nfsstate *stp, vnode_t vp, int cansleep,
        NFSPROC_T *p);
    static void nfsrv_freelockowner(struct nfsstate *stp, vnode_t vp, int cansleep,
        NFSPROC_T *p);
    static void nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp,
        int cansleep, NFSPROC_T *p);
    static void nfsrv_freenfslock(struct nfslock *lop);
    static void nfsrv_freenfslockfile(struct nfslockfile *lfp);
    static void nfsrv_freedeleg(struct nfsstate *);
    static int nfsrv_getstate(struct nfsclient *clp, nfsv4stateid_t *stateidp, 
        u_int32_t flags, struct nfsstate **stpp);
    static void nfsrv_getowner(struct nfsstatehead *hp, struct nfsstate *new_stp,
        struct nfsstate **stpp);
    static int nfsrv_getlockfh(vnode_t vp, u_short flags,
        struct nfslockfile **new_lfpp, fhandle_t *nfhp, NFSPROC_T *p);
    static int nfsrv_getlockfile(u_short flags, struct nfslockfile **new_lfpp,
        struct nfslockfile **lfpp, fhandle_t *nfhp, int lockit);
    static void nfsrv_insertlock(struct nfslock *new_lop,
        struct nfslock *insert_lop, struct nfsstate *stp, struct nfslockfile *lfp);
    static void nfsrv_updatelock(struct nfsstate *stp, struct nfslock **new_lopp,
        struct nfslock **other_lopp, struct nfslockfile *lfp);
    static int nfsrv_getipnumber(u_char *cp);
    static int nfsrv_checkrestart(nfsquad_t clientid, u_int32_t flags,
        nfsv4stateid_t *stateidp, int specialid);
    static int nfsrv_checkgrace(u_int32_t flags);
    static int nfsrv_docallback(struct nfsclient *clp, int procnum,
        nfsv4stateid_t *stateidp, int trunc, fhandle_t *fhp,
        struct nfsvattr *nap, nfsattrbit_t *attrbitp, NFSPROC_T *p);
    static u_int32_t nfsrv_nextclientindex(void);
    static u_int32_t nfsrv_nextstateindex(struct nfsclient *clp);
    static void nfsrv_markstable(struct nfsclient *clp);
    static int nfsrv_checkstable(struct nfsclient *clp);
   static int nfsrv_clientconflict(struct nfsclient *clp, int *haslockp, struct 
       vnode *vp, NFSPROC_T *p);
   static int nfsrv_delegconflict(struct nfsstate *stp, int *haslockp,
       NFSPROC_T *p, vnode_t vp);
   static int nfsrv_cleandeleg(vnode_t vp, struct nfslockfile *lfp,
       struct nfsclient *clp, int *haslockp, NFSPROC_T *p);
   static int nfsrv_notsamecredname(struct nfsrv_descript *nd,
       struct nfsclient *clp);
   static time_t nfsrv_leaseexpiry(void);
   static void nfsrv_delaydelegtimeout(struct nfsstate *stp);
   static int nfsrv_checkseqid(struct nfsrv_descript *nd, u_int32_t seqid,
       struct nfsstate *stp, struct nfsrvcache *op);
   static int nfsrv_nootherstate(struct nfsstate *stp);
   static int nfsrv_locallock(vnode_t vp, struct nfslockfile *lfp, int flags,
       uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p);
   static void nfsrv_localunlock(vnode_t vp, struct nfslockfile *lfp,
       uint64_t init_first, uint64_t init_end, NFSPROC_T *p);
   static int nfsrv_dolocal(vnode_t vp, struct nfslockfile *lfp, int flags,
       int oldflags, uint64_t first, uint64_t end, struct nfslockconflict *cfp,
       NFSPROC_T *p);
   static void nfsrv_locallock_rollback(vnode_t vp, struct nfslockfile *lfp,
       NFSPROC_T *p);
   static void nfsrv_locallock_commit(struct nfslockfile *lfp, int flags,
       uint64_t first, uint64_t end);
   static void nfsrv_locklf(struct nfslockfile *lfp);
   static void nfsrv_unlocklf(struct nfslockfile *lfp);
   
   /*
    * Scan the client list for a match and either return the current one,
    * create a new entry or return an error.
    * If returning a non-error, the clp structure must either be linked into
    * the client list or free'd.
    */
   APPLESTATIC int
   nfsrv_setclient(struct nfsrv_descript *nd, struct nfsclient **new_clpp,
       nfsquad_t *clientidp, nfsquad_t *confirmp, NFSPROC_T *p)
   {
           struct nfsclient *clp = NULL, *new_clp = *new_clpp;
           int i, error = 0;
           struct nfsstate *stp, *tstp;
           struct sockaddr_in *sad, *rad;
           int zapit = 0, gotit, hasstate = 0, igotlock;
           static u_int64_t confirm_index = 0;
   
           /*
            * Check for state resource limit exceeded.
            */
           if (nfsrv_openpluslock > NFSRV_V4STATELIMIT) {
                   error = NFSERR_RESOURCE;
                   goto out;
           }
   
           if (nfsrv_issuedelegs == 0 ||
               ((nd->nd_flag & ND_GSS) != 0 && nfsrv_nogsscallback != 0))
                   /*
                    * Don't do callbacks when delegations are disabled or
                    * for AUTH_GSS unless enabled via nfsrv_nogsscallback.
                    * If establishing a callback connection is attempted
                    * when a firewall is blocking the callback path, the
                    * server may wait too long for the connect attempt to
                    * succeed during the Open. Some clients, such as Linux,
                    * may timeout and give up on the Open before the server
                    * replies. Also, since AUTH_GSS callbacks are not
                    * yet interoperability tested, they might cause the
                    * server to crap out, if they get past the Init call to
                    * the client.
                    */
                   new_clp->lc_program = 0;
   
           /* Lock out other nfsd threads */
           NFSLOCKV4ROOTMUTEX();
           nfsv4_relref(&nfsv4rootfs_lock);
           do {
                   igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                       NFSV4ROOTLOCKMUTEXPTR, NULL);
           } while (!igotlock);
           NFSUNLOCKV4ROOTMUTEX();
   
           /*
            * Search for a match in the client list.
            */
           gotit = i = 0;
           while (i < NFSCLIENTHASHSIZE && !gotit) {
               LIST_FOREACH(clp, &nfsclienthash[i], lc_hash) {
                   if (new_clp->lc_idlen == clp->lc_idlen &&
                       !NFSBCMP(new_clp->lc_id, clp->lc_id, clp->lc_idlen)) {
                           gotit = 1;
                           break;
                   }
               }
               i++;
           }
           if (!gotit ||
               (clp->lc_flags & (LCL_NEEDSCONFIRM | LCL_ADMINREVOKED))) {
                   /*
                    * Get rid of the old one.
                    */
                   if (i != NFSCLIENTHASHSIZE) {
                           LIST_REMOVE(clp, lc_hash);
                           nfsrv_cleanclient(clp, p);
                           nfsrv_freedeleglist(&clp->lc_deleg);
                           nfsrv_freedeleglist(&clp->lc_olddeleg);
                           zapit = 1;
                   }
                   /*
                    * Add it after assigning a client id to it.
                    */
                   new_clp->lc_flags |= LCL_NEEDSCONFIRM;
                   confirmp->qval = new_clp->lc_confirm.qval = ++confirm_index;
                   clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
                       (u_int32_t)nfsrvboottime;
                   clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
                       nfsrv_nextclientindex();
                   new_clp->lc_stateindex = 0;
                   new_clp->lc_statemaxindex = 0;
                   new_clp->lc_cbref = 0;
                   new_clp->lc_expiry = nfsrv_leaseexpiry();
                   LIST_INIT(&new_clp->lc_open);
                   LIST_INIT(&new_clp->lc_deleg);
                   LIST_INIT(&new_clp->lc_olddeleg);
                   for (i = 0; i < NFSSTATEHASHSIZE; i++)
                           LIST_INIT(&new_clp->lc_stateid[i]);
                   LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
                       lc_hash);
                   newnfsstats.srvclients++;
                   nfsrv_openpluslock++;
                   nfsrv_clients++;
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_unlock(&nfsv4rootfs_lock, 1);
                   NFSUNLOCKV4ROOTMUTEX();
                   if (zapit)
                           nfsrv_zapclient(clp, p);
                   *new_clpp = NULL;
                   goto out;
           }
   
           /*
            * Now, handle the cases where the id is already issued.
            */
           if (nfsrv_notsamecredname(nd, clp)) {
               /*
                * Check to see if there is expired state that should go away.
                */
               if (clp->lc_expiry < NFSD_MONOSEC &&
                   (!LIST_EMPTY(&clp->lc_open) || !LIST_EMPTY(&clp->lc_deleg))) {
                   nfsrv_cleanclient(clp, p);
                   nfsrv_freedeleglist(&clp->lc_deleg);
               }
   
               /*
                * If there is outstanding state, then reply NFSERR_CLIDINUSE per
                * RFC3530 Sec. 8.1.2 last para.
                */
               if (!LIST_EMPTY(&clp->lc_deleg)) {
                   hasstate = 1;
               } else if (LIST_EMPTY(&clp->lc_open)) {
                   hasstate = 0;
               } else {
                   hasstate = 0;
                   /* Look for an Open on the OpenOwner */
                   LIST_FOREACH(stp, &clp->lc_open, ls_list) {
                       if (!LIST_EMPTY(&stp->ls_open)) {
                           hasstate = 1;
                           break;
                       }
                   }
               }
               if (hasstate) {
                   /*
                    * If the uid doesn't match, return NFSERR_CLIDINUSE after
                    * filling out the correct ipaddr and portnum.
                    */
                   sad = NFSSOCKADDR(new_clp->lc_req.nr_nam, struct sockaddr_in *);
                   rad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr_in *);
                   sad->sin_addr.s_addr = rad->sin_addr.s_addr;
                   sad->sin_port = rad->sin_port;
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_unlock(&nfsv4rootfs_lock, 1);
                   NFSUNLOCKV4ROOTMUTEX();
                   error = NFSERR_CLIDINUSE;
                   goto out;
               }
           }
   
           if (NFSBCMP(new_clp->lc_verf, clp->lc_verf, NFSX_VERF)) {
                   /*
                    * If the verifier has changed, the client has rebooted
                    * and a new client id is issued. The old state info
                    * can be thrown away once the SETCLIENTID_CONFIRM occurs.
                    */
                   LIST_REMOVE(clp, lc_hash);
                   new_clp->lc_flags |= LCL_NEEDSCONFIRM;
                   confirmp->qval = new_clp->lc_confirm.qval = ++confirm_index;
                   clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
                       nfsrvboottime;
                   clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
                       nfsrv_nextclientindex();
                   new_clp->lc_stateindex = 0;
                   new_clp->lc_statemaxindex = 0;
                   new_clp->lc_cbref = 0;
                   new_clp->lc_expiry = nfsrv_leaseexpiry();
   
                   /*
                    * Save the state until confirmed.
                    */
                   LIST_NEWHEAD(&new_clp->lc_open, &clp->lc_open, ls_list);
                   LIST_FOREACH(tstp, &new_clp->lc_open, ls_list)
                           tstp->ls_clp = new_clp;
                   LIST_NEWHEAD(&new_clp->lc_deleg, &clp->lc_deleg, ls_list);
                   LIST_FOREACH(tstp, &new_clp->lc_deleg, ls_list)
                           tstp->ls_clp = new_clp;
                   LIST_NEWHEAD(&new_clp->lc_olddeleg, &clp->lc_olddeleg,
                       ls_list);
                   LIST_FOREACH(tstp, &new_clp->lc_olddeleg, ls_list)
                           tstp->ls_clp = new_clp;
                   for (i = 0; i < NFSSTATEHASHSIZE; i++) {
                           LIST_NEWHEAD(&new_clp->lc_stateid[i],
                               &clp->lc_stateid[i], ls_hash);
                           LIST_FOREACH(tstp, &new_clp->lc_stateid[i], ls_hash)
                                   tstp->ls_clp = new_clp;
                   }
                   LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
                       lc_hash);
                   newnfsstats.srvclients++;
                   nfsrv_openpluslock++;
                   nfsrv_clients++;
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_unlock(&nfsv4rootfs_lock, 1);
                   NFSUNLOCKV4ROOTMUTEX();
   
                   /*
                    * Must wait until any outstanding callback on the old clp
                    * completes.
                    */
                   NFSLOCKSTATE();
                   while (clp->lc_cbref) {
                           clp->lc_flags |= LCL_WAKEUPWANTED;
                           (void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1,
                               "nfsd clp", 10 * hz);
                   }
                   NFSUNLOCKSTATE();
                   nfsrv_zapclient(clp, p);
                   *new_clpp = NULL;
                   goto out;
           }
           /*
            * id and verifier match, so update the net address info
            * and get rid of any existing callback authentication
            * handle, so a new one will be acquired.
            */
           LIST_REMOVE(clp, lc_hash);
           new_clp->lc_flags |= (LCL_NEEDSCONFIRM | LCL_DONTCLEAN);
           new_clp->lc_expiry = nfsrv_leaseexpiry();
           confirmp->qval = new_clp->lc_confirm.qval = ++confirm_index;
           clientidp->lval[0] = new_clp->lc_clientid.lval[0] =
               clp->lc_clientid.lval[0];
           clientidp->lval[1] = new_clp->lc_clientid.lval[1] =
               clp->lc_clientid.lval[1];
           new_clp->lc_delegtime = clp->lc_delegtime;
           new_clp->lc_stateindex = clp->lc_stateindex;
           new_clp->lc_statemaxindex = clp->lc_statemaxindex;
           new_clp->lc_cbref = 0;
           LIST_NEWHEAD(&new_clp->lc_open, &clp->lc_open, ls_list);
           LIST_FOREACH(tstp, &new_clp->lc_open, ls_list)
                   tstp->ls_clp = new_clp;
           LIST_NEWHEAD(&new_clp->lc_deleg, &clp->lc_deleg, ls_list);
           LIST_FOREACH(tstp, &new_clp->lc_deleg, ls_list)
                   tstp->ls_clp = new_clp;
           LIST_NEWHEAD(&new_clp->lc_olddeleg, &clp->lc_olddeleg, ls_list);
           LIST_FOREACH(tstp, &new_clp->lc_olddeleg, ls_list)
                   tstp->ls_clp = new_clp;
           for (i = 0; i < NFSSTATEHASHSIZE; i++) {
                   LIST_NEWHEAD(&new_clp->lc_stateid[i], &clp->lc_stateid[i],
                       ls_hash);
                   LIST_FOREACH(tstp, &new_clp->lc_stateid[i], ls_hash)
                           tstp->ls_clp = new_clp;
           }
           LIST_INSERT_HEAD(NFSCLIENTHASH(new_clp->lc_clientid), new_clp,
               lc_hash);
           newnfsstats.srvclients++;
           nfsrv_openpluslock++;
           nfsrv_clients++;
           NFSLOCKV4ROOTMUTEX();
           nfsv4_unlock(&nfsv4rootfs_lock, 1);
           NFSUNLOCKV4ROOTMUTEX();
   
           /*
            * Must wait until any outstanding callback on the old clp
            * completes.
            */
           NFSLOCKSTATE();
           while (clp->lc_cbref) {
                   clp->lc_flags |= LCL_WAKEUPWANTED;
                   (void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1, "nfsd clp",
                       10 * hz);
           }
           NFSUNLOCKSTATE();
           nfsrv_zapclient(clp, p);
           *new_clpp = NULL;
   
   out:
           NFSEXITCODE2(error, nd);
           return (error);
   }
   
   /*
    * Check to see if the client id exists and optionally confirm it.
    */
   APPLESTATIC int
   nfsrv_getclient(nfsquad_t clientid, int opflags, struct nfsclient **clpp,
       nfsquad_t confirm, struct nfsrv_descript *nd, NFSPROC_T *p)
   {
           struct nfsclient *clp;
           struct nfsstate *stp;
           int i;
           struct nfsclienthashhead *hp;
           int error = 0, igotlock, doneok;
   
           if (clpp)
                   *clpp = NULL;
           if (nfsrvboottime != clientid.lval[0]) {
                   error = NFSERR_STALECLIENTID;
                   goto out;
           }
   
           /*
            * If called with opflags == CLOPS_RENEW, the State Lock is
            * already held. Otherwise, we need to get either that or,
            * for the case of Confirm, lock out the nfsd threads.
            */
           if (opflags & CLOPS_CONFIRM) {
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_relref(&nfsv4rootfs_lock);
                   do {
                           igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                               NFSV4ROOTLOCKMUTEXPTR, NULL);
                   } while (!igotlock);
                   NFSUNLOCKV4ROOTMUTEX();
           } else if (opflags != CLOPS_RENEW) {
                   NFSLOCKSTATE();
           }
   
           hp = NFSCLIENTHASH(clientid);
           LIST_FOREACH(clp, hp, lc_hash) {
                   if (clp->lc_clientid.lval[1] == clientid.lval[1])
                           break;
           }
           if (clp == LIST_END(hp)) {
                   if (opflags & CLOPS_CONFIRM)
                           error = NFSERR_STALECLIENTID;
                   else
                           error = NFSERR_EXPIRED;
           } else if (clp->lc_flags & LCL_ADMINREVOKED) {
                   /*
                    * If marked admin revoked, just return the error.
                    */
                   error = NFSERR_ADMINREVOKED;
           }
           if (error) {
                   if (opflags & CLOPS_CONFIRM) {
                           NFSLOCKV4ROOTMUTEX();
                           nfsv4_unlock(&nfsv4rootfs_lock, 1);
                           NFSUNLOCKV4ROOTMUTEX();
                   } else if (opflags != CLOPS_RENEW) {
                           NFSUNLOCKSTATE();
                   }
                   goto out;
           }
   
           /*
            * Perform any operations specified by the opflags.
            */
           if (opflags & CLOPS_CONFIRM) {
                   if (clp->lc_confirm.qval != confirm.qval)
                           error = NFSERR_STALECLIENTID;
                   else if (nfsrv_notsamecredname(nd, clp))
                           error = NFSERR_CLIDINUSE;
   
                   if (!error) {
                       if ((clp->lc_flags & (LCL_NEEDSCONFIRM | LCL_DONTCLEAN)) ==
                           LCL_NEEDSCONFIRM) {
                           /*
                            * Hang onto the delegations (as old delegations)
                            * for an Open with CLAIM_DELEGATE_PREV unless in
                            * grace, but get rid of the rest of the state.
                            */
                           nfsrv_cleanclient(clp, p);
                           nfsrv_freedeleglist(&clp->lc_olddeleg);
                           if (nfsrv_checkgrace(0)) {
                               /* In grace, so just delete delegations */
                               nfsrv_freedeleglist(&clp->lc_deleg);
                           } else {
                               LIST_FOREACH(stp, &clp->lc_deleg, ls_list)
                                   stp->ls_flags |= NFSLCK_OLDDELEG;
                               clp->lc_delegtime = NFSD_MONOSEC +
                                   nfsrv_lease + NFSRV_LEASEDELTA;
                               LIST_NEWHEAD(&clp->lc_olddeleg, &clp->lc_deleg,
                                   ls_list);
                           }
                       }
                       clp->lc_flags &= ~(LCL_NEEDSCONFIRM | LCL_DONTCLEAN);
                       if (clp->lc_program)
                           clp->lc_flags |= LCL_NEEDSCBNULL;
                   }
           } else if (clp->lc_flags & LCL_NEEDSCONFIRM) {
                   error = NFSERR_EXPIRED;
           }
   
           /*
            * If called by the Renew Op, we must check the principal.
            */
           if (!error && (opflags & CLOPS_RENEWOP)) {
               if (nfsrv_notsamecredname(nd, clp)) {
                   doneok = 0;
                   for (i = 0; i < NFSSTATEHASHSIZE && doneok == 0; i++) {
                       LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                           if ((stp->ls_flags & NFSLCK_OPEN) &&
                               stp->ls_uid == nd->nd_cred->cr_uid) {
                                   doneok = 1;
                                   break;
                           }
                       }
                   }
                   if (!doneok)
                           error = NFSERR_ACCES;
               }
               if (!error && (clp->lc_flags & LCL_CBDOWN))
                   error = NFSERR_CBPATHDOWN;
           }
           if ((!error || error == NFSERR_CBPATHDOWN) &&
                (opflags & CLOPS_RENEW)) {
                   clp->lc_expiry = nfsrv_leaseexpiry();
           }
           if (opflags & CLOPS_CONFIRM) {
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_unlock(&nfsv4rootfs_lock, 1);
                   NFSUNLOCKV4ROOTMUTEX();
           } else if (opflags != CLOPS_RENEW) {
                   NFSUNLOCKSTATE();
           }
           if (clpp)
                   *clpp = clp;
   
   out:
           NFSEXITCODE2(error, nd);
           return (error);
   }
   
   /*
    * Called from the new nfssvc syscall to admin revoke a clientid.
    * Returns 0 for success, error otherwise.
    */
   APPLESTATIC int
   nfsrv_adminrevoke(struct nfsd_clid *revokep, NFSPROC_T *p)
   {
           struct nfsclient *clp = NULL;
           int i, error = 0;
           int gotit, igotlock;
   
           /*
            * First, lock out the nfsd so that state won't change while the
            * revocation record is being written to the stable storage restart
            * file.
            */
           NFSLOCKV4ROOTMUTEX();
           do {
                   igotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                       NFSV4ROOTLOCKMUTEXPTR, NULL);
           } while (!igotlock);
           NFSUNLOCKV4ROOTMUTEX();
   
           /*
            * Search for a match in the client list.
            */
           gotit = i = 0;
           while (i < NFSCLIENTHASHSIZE && !gotit) {
               LIST_FOREACH(clp, &nfsclienthash[i], lc_hash) {
                   if (revokep->nclid_idlen == clp->lc_idlen &&
                       !NFSBCMP(revokep->nclid_id, clp->lc_id, clp->lc_idlen)) {
                           gotit = 1;
                           break;
                   }
               }
               i++;
           }
           if (!gotit) {
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_unlock(&nfsv4rootfs_lock, 0);
                   NFSUNLOCKV4ROOTMUTEX();
                   error = EPERM;
                   goto out;
           }
   
           /*
            * Now, write out the revocation record
            */
           nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
           nfsrv_backupstable();
   
           /*
            * and clear out the state, marking the clientid revoked.
            */
           clp->lc_flags &= ~LCL_CALLBACKSON;
           clp->lc_flags |= LCL_ADMINREVOKED;
           nfsrv_cleanclient(clp, p);
           nfsrv_freedeleglist(&clp->lc_deleg);
           nfsrv_freedeleglist(&clp->lc_olddeleg);
           NFSLOCKV4ROOTMUTEX();
           nfsv4_unlock(&nfsv4rootfs_lock, 0);
           NFSUNLOCKV4ROOTMUTEX();
   
   out:
           NFSEXITCODE(error);
           return (error);
   }
   
   /*
    * Dump out stats for all clients. Called from nfssvc(2), that is used
    * newnfsstats.
    */
   APPLESTATIC void
   nfsrv_dumpclients(struct nfsd_dumpclients *dumpp, int maxcnt)
   {
           struct nfsclient *clp;
           int i = 0, cnt = 0;
   
           /*
            * First, get a reference on the nfsv4rootfs_lock so that an
            * exclusive lock cannot be acquired while dumping the clients.
            */
           NFSLOCKV4ROOTMUTEX();
           nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
           NFSUNLOCKV4ROOTMUTEX();
           NFSLOCKSTATE();
           /*
            * Rattle through the client lists until done.
            */
           while (i < NFSCLIENTHASHSIZE && cnt < maxcnt) {
               clp = LIST_FIRST(&nfsclienthash[i]);
               while (clp != LIST_END(&nfsclienthash[i]) && cnt < maxcnt) {
                   nfsrv_dumpaclient(clp, &dumpp[cnt]);
                   cnt++;
                   clp = LIST_NEXT(clp, lc_hash);
               }
               i++;
           }
           if (cnt < maxcnt)
               dumpp[cnt].ndcl_clid.nclid_idlen = 0;
           NFSUNLOCKSTATE();
           NFSLOCKV4ROOTMUTEX();
           nfsv4_relref(&nfsv4rootfs_lock);
           NFSUNLOCKV4ROOTMUTEX();
   }
   
   /*
    * Dump stats for a client. Must be called with the NFSSTATELOCK and spl'd.
    */
   static void
   nfsrv_dumpaclient(struct nfsclient *clp, struct nfsd_dumpclients *dumpp)
   {
           struct nfsstate *stp, *openstp, *lckownstp;
           struct nfslock *lop;
           struct sockaddr *sad;
           struct sockaddr_in *rad;
           struct sockaddr_in6 *rad6;
   
           dumpp->ndcl_nopenowners = dumpp->ndcl_nlockowners = 0;
           dumpp->ndcl_nopens = dumpp->ndcl_nlocks = 0;
           dumpp->ndcl_ndelegs = dumpp->ndcl_nolddelegs = 0;
           dumpp->ndcl_flags = clp->lc_flags;
           dumpp->ndcl_clid.nclid_idlen = clp->lc_idlen;
           NFSBCOPY(clp->lc_id, dumpp->ndcl_clid.nclid_id, clp->lc_idlen);
           sad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr *);
           dumpp->ndcl_addrfam = sad->sa_family;
           if (sad->sa_family == AF_INET) {
                   rad = (struct sockaddr_in *)sad;
                   dumpp->ndcl_cbaddr.sin_addr = rad->sin_addr;
           } else {
                   rad6 = (struct sockaddr_in6 *)sad;
                   dumpp->ndcl_cbaddr.sin6_addr = rad6->sin6_addr;
           }
   
           /*
            * Now, scan the state lists and total up the opens and locks.
            */
           LIST_FOREACH(stp, &clp->lc_open, ls_list) {
               dumpp->ndcl_nopenowners++;
               LIST_FOREACH(openstp, &stp->ls_open, ls_list) {
                   dumpp->ndcl_nopens++;
                   LIST_FOREACH(lckownstp, &openstp->ls_open, ls_list) {
                       dumpp->ndcl_nlockowners++;
                       LIST_FOREACH(lop, &lckownstp->ls_lock, lo_lckowner) {
                           dumpp->ndcl_nlocks++;
                       }
                   }
               }
           }
   
           /*
            * and the delegation lists.
            */
           LIST_FOREACH(stp, &clp->lc_deleg, ls_list) {
               dumpp->ndcl_ndelegs++;
           }
           LIST_FOREACH(stp, &clp->lc_olddeleg, ls_list) {
               dumpp->ndcl_nolddelegs++;
           }
   }
   
   /*
    * Dump out lock stats for a file.
    */
   APPLESTATIC void
   nfsrv_dumplocks(vnode_t vp, struct nfsd_dumplocks *ldumpp, int maxcnt,
       NFSPROC_T *p)
   {
           struct nfsstate *stp;
           struct nfslock *lop;
           int cnt = 0;
           struct nfslockfile *lfp;
           struct sockaddr *sad;
           struct sockaddr_in *rad;
           struct sockaddr_in6 *rad6;
           int ret;
           fhandle_t nfh;
   
           ret = nfsrv_getlockfh(vp, 0, NULL, &nfh, p);
           /*
            * First, get a reference on the nfsv4rootfs_lock so that an
            * exclusive lock on it cannot be acquired while dumping the locks.
            */
           NFSLOCKV4ROOTMUTEX();
           nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
           NFSUNLOCKV4ROOTMUTEX();
           NFSLOCKSTATE();
           if (!ret)
                   ret = nfsrv_getlockfile(0, NULL, &lfp, &nfh, 0);
           if (ret) {
                   ldumpp[0].ndlck_clid.nclid_idlen = 0;
                   NFSUNLOCKSTATE();
                   NFSLOCKV4ROOTMUTEX();
                   nfsv4_relref(&nfsv4rootfs_lock);
                   NFSUNLOCKV4ROOTMUTEX();
                   return;
           }
   
           /*
            * For each open share on file, dump it out.
            */
           stp = LIST_FIRST(&lfp->lf_open);
           while (stp != LIST_END(&lfp->lf_open) && cnt < maxcnt) {
                   ldumpp[cnt].ndlck_flags = stp->ls_flags;
                   ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                   ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                   ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                   ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                   ldumpp[cnt].ndlck_owner.nclid_idlen =
                       stp->ls_openowner->ls_ownerlen;
                   NFSBCOPY(stp->ls_openowner->ls_owner,
                       ldumpp[cnt].ndlck_owner.nclid_id,
                       stp->ls_openowner->ls_ownerlen);
                   ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                   NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                       stp->ls_clp->lc_idlen);
                   sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                   ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                   if (sad->sa_family == AF_INET) {
                           rad = (struct sockaddr_in *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                   } else {
                           rad6 = (struct sockaddr_in6 *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                   }
                   stp = LIST_NEXT(stp, ls_file);
                   cnt++;
           }
   
           /*
            * and all locks.
            */
           lop = LIST_FIRST(&lfp->lf_lock);
           while (lop != LIST_END(&lfp->lf_lock) && cnt < maxcnt) {
                   stp = lop->lo_stp;
                   ldumpp[cnt].ndlck_flags = lop->lo_flags;
                   ldumpp[cnt].ndlck_first = lop->lo_first;
                   ldumpp[cnt].ndlck_end = lop->lo_end;
                   ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                   ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                   ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                   ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                   ldumpp[cnt].ndlck_owner.nclid_idlen = stp->ls_ownerlen;
                   NFSBCOPY(stp->ls_owner, ldumpp[cnt].ndlck_owner.nclid_id,
                       stp->ls_ownerlen);
                   ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                   NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                       stp->ls_clp->lc_idlen);
                   sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                   ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                   if (sad->sa_family == AF_INET) {
                           rad = (struct sockaddr_in *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                   } else {
                           rad6 = (struct sockaddr_in6 *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                   }
                   lop = LIST_NEXT(lop, lo_lckfile);
                   cnt++;
           }
   
           /*
            * and the delegations.
            */
           stp = LIST_FIRST(&lfp->lf_deleg);
           while (stp != LIST_END(&lfp->lf_deleg) && cnt < maxcnt) {
                   ldumpp[cnt].ndlck_flags = stp->ls_flags;
                   ldumpp[cnt].ndlck_stateid.seqid = stp->ls_stateid.seqid;
                   ldumpp[cnt].ndlck_stateid.other[0] = stp->ls_stateid.other[0];
                   ldumpp[cnt].ndlck_stateid.other[1] = stp->ls_stateid.other[1];
                   ldumpp[cnt].ndlck_stateid.other[2] = stp->ls_stateid.other[2];
                   ldumpp[cnt].ndlck_owner.nclid_idlen = 0;
                   ldumpp[cnt].ndlck_clid.nclid_idlen = stp->ls_clp->lc_idlen;
                   NFSBCOPY(stp->ls_clp->lc_id, ldumpp[cnt].ndlck_clid.nclid_id,
                       stp->ls_clp->lc_idlen);
                   sad=NFSSOCKADDR(stp->ls_clp->lc_req.nr_nam, struct sockaddr *);
                   ldumpp[cnt].ndlck_addrfam = sad->sa_family;
                   if (sad->sa_family == AF_INET) {
                           rad = (struct sockaddr_in *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin_addr = rad->sin_addr;
                   } else {
                           rad6 = (struct sockaddr_in6 *)sad;
                           ldumpp[cnt].ndlck_cbaddr.sin6_addr = rad6->sin6_addr;
                   }
                   stp = LIST_NEXT(stp, ls_file);
                   cnt++;
           }
   
           /*
            * If list isn't full, mark end of list by setting the client name
            * to zero length.
            */
           if (cnt < maxcnt)
                   ldumpp[cnt].ndlck_clid.nclid_idlen = 0;
           NFSUNLOCKSTATE();
           NFSLOCKV4ROOTMUTEX();
           nfsv4_relref(&nfsv4rootfs_lock);
           NFSUNLOCKV4ROOTMUTEX();
   }
   
   /*
    * Server timer routine. It can scan any linked list, so long
    * as it holds the spin/mutex lock and there is no exclusive lock on
    * nfsv4rootfs_lock.
    * (For OpenBSD, a kthread is ok. For FreeBSD, I think it is ok
    *  to do this from a callout, since the spin locks work. For
    *  Darwin, I'm not sure what will work correctly yet.)
    * Should be called once per second.
    */
   APPLESTATIC void
   nfsrv_servertimer(void)
   {
           struct nfsclient *clp, *nclp;
           struct nfsstate *stp, *nstp;
           int got_ref, i;
   
           /*
            * Make sure nfsboottime is set. This is used by V3 as well
            * as V4. Note that nfsboottime is not nfsrvboottime, which is
            * only used by the V4 server for leases.
            */
           if (nfsboottime.tv_sec == 0)
                   NFSSETBOOTTIME(nfsboottime);
   
           /*
            * If server hasn't started yet, just return.
            */
           NFSLOCKSTATE();
           if (nfsrv_stablefirst.nsf_eograce == 0) {
                   NFSUNLOCKSTATE();
                   return;
           }
           if (!(nfsrv_stablefirst.nsf_flags & NFSNSF_UPDATEDONE)) {
                   if (!(nfsrv_stablefirst.nsf_flags & NFSNSF_GRACEOVER) &&
                       NFSD_MONOSEC > nfsrv_stablefirst.nsf_eograce)
                           nfsrv_stablefirst.nsf_flags |=
                               (NFSNSF_GRACEOVER | NFSNSF_NEEDLOCK);
                   NFSUNLOCKSTATE();
                   return;
           }
   
           /*
            * Try and get a reference count on the nfsv4rootfs_lock so that
            * no nfsd thread can acquire an exclusive lock on it before this
            * call is done. If it is already exclusively locked, just return.
            */
           NFSLOCKV4ROOTMUTEX();
           got_ref = nfsv4_getref_nonblock(&nfsv4rootfs_lock);
           NFSUNLOCKV4ROOTMUTEX();
           if (got_ref == 0) {
                   NFSUNLOCKSTATE();
                   return;
           }
   
           /*
            * For each client...
            */
           for (i = 0; i < NFSCLIENTHASHSIZE; i++) {
               clp = LIST_FIRST(&nfsclienthash[i]);
               while (clp != LIST_END(&nfsclienthash[i])) {
                   nclp = LIST_NEXT(clp, lc_hash);
                   if (!(clp->lc_flags & LCL_EXPIREIT)) {
                       if (((clp->lc_expiry + NFSRV_STALELEASE) < NFSD_MONOSEC
                            && ((LIST_EMPTY(&clp->lc_deleg)
                                 && LIST_EMPTY(&clp->lc_open)) ||
                                nfsrv_clients > nfsrv_clienthighwater)) ||
                           (clp->lc_expiry + NFSRV_MOULDYLEASE) < NFSD_MONOSEC ||
                           (clp->lc_expiry < NFSD_MONOSEC &&
                            (nfsrv_openpluslock * 10 / 9) > NFSRV_V4STATELIMIT)) {
                           /*
                            * Lease has expired several nfsrv_lease times ago:
                            * PLUS
                            *    - no state is associated with it
                            *    OR
                            *    - above high water mark for number of clients
                            *      (nfsrv_clienthighwater should be large enough
                            *       that this only occurs when clients fail to
                            *       use the same nfs_client_id4.id. Maybe somewhat
                            *       higher that the maximum number of clients that
                            *       will mount this server?)
                            * OR
                            * Lease has expired a very long time ago
                            * OR
                            * Lease has expired PLUS the number of opens + locks
                            * has exceeded 90% of capacity
                            *
                            * --> Mark for expiry. The actual expiry will be done
                            *     by an nfsd sometime soon.
                            */
                           clp->lc_flags |= LCL_EXPIREIT;
                           nfsrv_stablefirst.nsf_flags |=
                               (NFSNSF_NEEDLOCK | NFSNSF_EXPIREDCLIENT);
                       } else {
                           /*
                            * If there are no opens, increment no open tick cnt
                            * If time exceeds NFSNOOPEN, mark it to be thrown away
                            * otherwise, if there is an open, reset no open time
                            * Hopefully, this will avoid excessive re-creation
                            * of open owners and subsequent open confirms.
                            */
                           stp = LIST_FIRST(&clp->lc_open);
                           while (stp != LIST_END(&clp->lc_open)) {
                                   nstp = LIST_NEXT(stp, ls_list);
                                   if (LIST_EMPTY(&stp->ls_open)) {
                                           stp->ls_noopens++;
                                           if (stp->ls_noopens > NFSNOOPEN ||
                                               (nfsrv_openpluslock * 2) >
                                               NFSRV_V4STATELIMIT)
                                                   nfsrv_stablefirst.nsf_flags |=
                                                           NFSNSF_NOOPENS;
                                   } else {
                                           stp->ls_noopens = 0;
                                   }
                                   stp = nstp;
                           }
                       }
                   }
                   clp = nclp;
               }
           }
           NFSUNLOCKSTATE();
           NFSLOCKV4ROOTMUTEX();
           nfsv4_relref(&nfsv4rootfs_lock);
           NFSUNLOCKV4ROOTMUTEX();
   }
   
   /*
    * The following set of functions free up the various data structures.
    */
   /*
    * Clear out all open/lock state related to this nfsclient.
    * Caller must hold an exclusive lock on nfsv4rootfs_lock, so that
    * there are no other active nfsd threads.
    */
   APPLESTATIC void
   nfsrv_cleanclient(struct nfsclient *clp, NFSPROC_T *p)
   {
           struct nfsstate *stp, *nstp;
   
           LIST_FOREACH_SAFE(stp, &clp->lc_open, ls_list, nstp)
                   nfsrv_freeopenowner(stp, 1, p);
   }
   
   /*
    * Free a client that has been cleaned. It should also already have been
    * removed from the lists.
    * (Just to be safe w.r.t. newnfs_disconnect(), call this function when
    *  softclock interrupts are enabled.)
    */
   APPLESTATIC void
   nfsrv_zapclient(struct nfsclient *clp, NFSPROC_T *p)
   {
  
  #ifdef notyet
          if ((clp->lc_flags & (LCL_GSS | LCL_CALLBACKSON)) ==
               (LCL_GSS | LCL_CALLBACKSON) &&
              (clp->lc_hand.nfsh_flag & NFSG_COMPLETE) &&
              clp->lc_handlelen > 0) {
                  clp->lc_hand.nfsh_flag &= ~NFSG_COMPLETE;
                  clp->lc_hand.nfsh_flag |= NFSG_DESTROYED;
                  (void) nfsrv_docallback(clp, NFSV4PROC_CBNULL,
                          NULL, 0, NULL, NULL, NULL, p);
          }
  #endif
          newnfs_disconnect(&clp->lc_req);
          NFSSOCKADDRFREE(clp->lc_req.nr_nam);
          NFSFREEMUTEX(&clp->lc_req.nr_mtx);
          free((caddr_t)clp, M_NFSDCLIENT);
          NFSLOCKSTATE();
          newnfsstats.srvclients--;
          nfsrv_openpluslock--;
          nfsrv_clients--;
          NFSUNLOCKSTATE();
  }
  
  /*
   * Free a list of delegation state structures.
   * (This function will also free all nfslockfile structures that no
   *  longer have associated state.)
   */
  APPLESTATIC void
  nfsrv_freedeleglist(struct nfsstatehead *sthp)
  {
          struct nfsstate *stp, *nstp;
  
          LIST_FOREACH_SAFE(stp, sthp, ls_list, nstp) {
                  nfsrv_freedeleg(stp);
          }
          LIST_INIT(sthp);
  }
  
  /*
   * Free up a delegation.
   */
  static void
  nfsrv_freedeleg(struct nfsstate *stp)
  {
          struct nfslockfile *lfp;
  
          LIST_REMOVE(stp, ls_hash);
          LIST_REMOVE(stp, ls_list);
          LIST_REMOVE(stp, ls_file);
          lfp = stp->ls_lfp;
          if (LIST_EMPTY(&lfp->lf_open) &&
              LIST_EMPTY(&lfp->lf_lock) && LIST_EMPTY(&lfp->lf_deleg) &&
              LIST_EMPTY(&lfp->lf_locallock) && LIST_EMPTY(&lfp->lf_rollback) &&
              lfp->lf_usecount == 0 &&
              nfsv4_testlock(&lfp->lf_locallock_lck) == 0)
                  nfsrv_freenfslockfile(lfp);
          FREE((caddr_t)stp, M_NFSDSTATE);
          newnfsstats.srvdelegates--;
          nfsrv_openpluslock--;
          nfsrv_delegatecnt--;
  }
  
  /*
   * This function frees an open owner and all associated opens.
   */
  static void
  nfsrv_freeopenowner(struct nfsstate *stp, int cansleep, NFSPROC_T *p)
  {
          struct nfsstate *nstp, *tstp;
  
          LIST_REMOVE(stp, ls_list);
          /*
           * Now, free all associated opens.
           */
          nstp = LIST_FIRST(&stp->ls_open);
          while (nstp != LIST_END(&stp->ls_open)) {
                  tstp = nstp;
                  nstp = LIST_NEXT(nstp, ls_list);
                  (void) nfsrv_freeopen(tstp, NULL, cansleep, p);
          }
          if (stp->ls_op)
                  nfsrvd_derefcache(stp->ls_op);
          FREE((caddr_t)stp, M_NFSDSTATE);
          newnfsstats.srvopenowners--;
          nfsrv_openpluslock--;
  }
  
  /*
   * This function frees an open (nfsstate open structure) with all associated
   * lock_owners and locks. It also frees the nfslockfile structure iff there
   * are no other opens on the file.
   * Returns 1 if it free'd the nfslockfile, 0 otherwise.
   */
  static int
  nfsrv_freeopen(struct nfsstate *stp, vnode_t vp, int cansleep, NFSPROC_T *p)
  {
          struct nfsstate *nstp, *tstp;
          struct nfslockfile *lfp;
          int ret;
  
          LIST_REMOVE(stp, ls_hash);
          LIST_REMOVE(stp, ls_list);
          LIST_REMOVE(stp, ls_file);
  
          lfp = stp->ls_lfp;
          /*
           * Now, free all lockowners associated with this open.
           */
          LIST_FOREACH_SAFE(tstp, &stp->ls_open, ls_list, nstp)
                  nfsrv_freelockowner(tstp, vp, cansleep, p);
  
          /*
           * The nfslockfile is freed here if there are no locks
           * associated with the open.
           * If there are locks associated with the open, the
           * nfslockfile structure can be freed via nfsrv_freelockowner().
           * Acquire the state mutex to avoid races with calls to
           * nfsrv_getlockfile().
           */
          if (cansleep != 0)
                  NFSLOCKSTATE();
          if (lfp != NULL && LIST_EMPTY(&lfp->lf_open) &&
              LIST_EMPTY(&lfp->lf_deleg) && LIST_EMPTY(&lfp->lf_lock) &&
              LIST_EMPTY(&lfp->lf_locallock) && LIST_EMPTY(&lfp->lf_rollback) &&
              lfp->lf_usecount == 0 &&
              (cansleep != 0 || nfsv4_testlock(&lfp->lf_locallock_lck) == 0)) {
                  nfsrv_freenfslockfile(lfp);
                  ret = 1;
          } else
                  ret = 0;
          if (cansleep != 0)
                  NFSUNLOCKSTATE();
          FREE((caddr_t)stp, M_NFSDSTATE);
          newnfsstats.srvopens--;
          nfsrv_openpluslock--;
          return (ret);
  }
  
  /*
   * Frees a lockowner and all associated locks.
   */
  static void
  nfsrv_freelockowner(struct nfsstate *stp, vnode_t vp, int cansleep,
      NFSPROC_T *p)
  {
  
          LIST_REMOVE(stp, ls_hash);
          LIST_REMOVE(stp, ls_list);
          nfsrv_freeallnfslocks(stp, vp, cansleep, p);
          if (stp->ls_op)
                  nfsrvd_derefcache(stp->ls_op);
          FREE((caddr_t)stp, M_NFSDSTATE);
          newnfsstats.srvlockowners--;
          nfsrv_openpluslock--;
  }
  
  /*
   * Free all the nfs locks on a lockowner.
   */
  static void
  nfsrv_freeallnfslocks(struct nfsstate *stp, vnode_t vp, int cansleep,
      NFSPROC_T *p)
  {
          struct nfslock *lop, *nlop;
          struct nfsrollback *rlp, *nrlp;
          struct nfslockfile *lfp = NULL;
          int gottvp = 0;
          vnode_t tvp = NULL;
          uint64_t first, end;
  
          lop = LIST_FIRST(&stp->ls_lock);
          while (lop != LIST_END(&stp->ls_lock)) {
                  nlop = LIST_NEXT(lop, lo_lckowner);
                  /*
                   * Since all locks should be for the same file, lfp should
                   * not change.
                   */
                  if (lfp == NULL)
                          lfp = lop->lo_lfp;
                  else if (lfp != lop->lo_lfp)
                          panic("allnfslocks");
                  /*
                   * If vp is NULL and cansleep != 0, a vnode must be acquired
                   * from the file handle. This only occurs when called from
                   * nfsrv_cleanclient().
                   */
                  if (gottvp == 0) {
                          if (nfsrv_dolocallocks == 0)
                                  tvp = NULL;
                          else if (vp == NULL && cansleep != 0)
                                  tvp = nfsvno_getvp(&lfp->lf_fh);
                          else
                                  tvp = vp;
                          gottvp = 1;
                  }
  
                  if (tvp != NULL) {
                          if (cansleep == 0)
                                  panic("allnfs2");
                          first = lop->lo_first;
                          end = lop->lo_end;
                          nfsrv_freenfslock(lop);
                          nfsrv_localunlock(tvp, lfp, first, end, p);
                          LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list,
                              nrlp)
                                  free(rlp, M_NFSDROLLBACK);
                          LIST_INIT(&lfp->lf_rollback);
                  } else
                          nfsrv_freenfslock(lop);
                  lop = nlop;
          }
          if (vp == NULL && tvp != NULL)
                  vput(tvp);
  }
  
  /*
   * Free an nfslock structure.
   */
  static void
  nfsrv_freenfslock(struct nfslock *lop)
  {
  
          if (lop->lo_lckfile.le_prev != NULL) {
                  LIST_REMOVE(lop, lo_lckfile);
                  newnfsstats.srvlocks--;
                  nfsrv_openpluslock--;
          }
          LIST_REMOVE(lop, lo_lckowner);
          FREE((caddr_t)lop, M_NFSDLOCK);
  }
  
  /*
   * This function frees an nfslockfile structure.
   */
  static void
  nfsrv_freenfslockfile(struct nfslockfile *lfp)
  {
  
          LIST_REMOVE(lfp, lf_hash);
          FREE((caddr_t)lfp, M_NFSDLOCKFILE);
  }
  
  /*
   * This function looks up an nfsstate structure via stateid.
   */
  static int
  nfsrv_getstate(struct nfsclient *clp, nfsv4stateid_t *stateidp, __unused u_int32_t flags,
      struct nfsstate **stpp)
  {
          struct nfsstate *stp;
          struct nfsstatehead *hp;
          int error = 0;
  
          *stpp = NULL;
          hp = NFSSTATEHASH(clp, *stateidp);
          LIST_FOREACH(stp, hp, ls_hash) {
                  if (!NFSBCMP(stp->ls_stateid.other, stateidp->other,
                          NFSX_STATEIDOTHER))
                          break;
          }
  
          /*
           * If no state id in list, return NFSERR_BADSTATEID.
           */
          if (stp == LIST_END(hp)) {
                  error = NFSERR_BADSTATEID;
                  goto out;
          }
          *stpp = stp;
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * This function gets an nfsstate structure via owner string.
   */
  static void
  nfsrv_getowner(struct nfsstatehead *hp, struct nfsstate *new_stp,
      struct nfsstate **stpp)
  {
          struct nfsstate *stp;
  
          *stpp = NULL;
          LIST_FOREACH(stp, hp, ls_list) {
                  if (new_stp->ls_ownerlen == stp->ls_ownerlen &&
                    !NFSBCMP(new_stp->ls_owner,stp->ls_owner,stp->ls_ownerlen)) {
                          *stpp = stp;
                          return;
                  }
          }
  }
  
  /*
   * Lock control function called to update lock status.
   * Returns 0 upon success, -1 if there is no lock and the flags indicate
   * that one isn't to be created and an NFSERR_xxx for other errors.
   * The structures new_stp and new_lop are passed in as pointers that should
   * be set to NULL if the structure is used and shouldn't be free'd.
   * For the NFSLCK_TEST and NFSLCK_CHECK cases, the structures are
   * never used and can safely be allocated on the stack. For all other
   * cases, *new_stpp and *new_lopp should be malloc'd before the call,
   * in case they are used.
   */
  APPLESTATIC int
  nfsrv_lockctrl(vnode_t vp, struct nfsstate **new_stpp,
      struct nfslock **new_lopp, struct nfslockconflict *cfp,
      nfsquad_t clientid, nfsv4stateid_t *stateidp,
      __unused struct nfsexstuff *exp,
      struct nfsrv_descript *nd, NFSPROC_T *p)
  {
          struct nfslock *lop;
          struct nfsstate *new_stp = *new_stpp;
          struct nfslock *new_lop = *new_lopp;
          struct nfsstate *tstp, *mystp, *nstp;
          int specialid = 0;
          struct nfslockfile *lfp;
          struct nfslock *other_lop = NULL;
          struct nfsstate *stp, *lckstp = NULL;
          struct nfsclient *clp = NULL;
          u_int32_t bits;
          int error = 0, haslock = 0, ret, reterr;
          int getlckret, delegation = 0, filestruct_locked;
          fhandle_t nfh;
          uint64_t first, end;
          uint32_t lock_flags;
  
          if (new_stp->ls_flags & (NFSLCK_CHECK | NFSLCK_SETATTR)) {
                  /*
                   * Note the special cases of "all 1s" or "all 0s" stateids and
                   * let reads with all 1s go ahead.
                   */
                  if (new_stp->ls_stateid.seqid == 0x0 &&
                      new_stp->ls_stateid.other[0] == 0x0 &&
                      new_stp->ls_stateid.other[1] == 0x0 &&
                      new_stp->ls_stateid.other[2] == 0x0)
                          specialid = 1;
                  else if (new_stp->ls_stateid.seqid == 0xffffffff &&
                      new_stp->ls_stateid.other[0] == 0xffffffff &&
                      new_stp->ls_stateid.other[1] == 0xffffffff &&
                      new_stp->ls_stateid.other[2] == 0xffffffff)
                          specialid = 2;
          }
  
          /*
           * Check for restart conditions (client and server).
           */
          error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
              &new_stp->ls_stateid, specialid);
          if (error)
                  goto out;
  
          /*
           * Check for state resource limit exceeded.
           */
          if ((new_stp->ls_flags & NFSLCK_LOCK) &&
              nfsrv_openpluslock > NFSRV_V4STATELIMIT) {
                  error = NFSERR_RESOURCE;
                  goto out;
          }
  
          /*
           * For the lock case, get another nfslock structure,
           * just in case we need it.
           * Malloc now, before we start sifting through the linked lists,
           * in case we have to wait for memory.
           */
  tryagain:
          if (new_stp->ls_flags & NFSLCK_LOCK)
                  MALLOC(other_lop, struct nfslock *, sizeof (struct nfslock),
                      M_NFSDLOCK, M_WAITOK);
          filestruct_locked = 0;
          reterr = 0;
          lfp = NULL;
  
          /*
           * Get the lockfile structure for CFH now, so we can do a sanity
           * check against the stateid, before incrementing the seqid#, since
           * we want to return NFSERR_BADSTATEID on failure and the seqid#
           * shouldn't be incremented for this case.
           * If nfsrv_getlockfile() returns -1, it means "not found", which
           * will be handled later.
           * If we are doing Lock/LockU and local locking is enabled, sleep
           * lock the nfslockfile structure.
           */
          getlckret = nfsrv_getlockfh(vp, new_stp->ls_flags, NULL, &nfh, p);
          NFSLOCKSTATE();
          if (getlckret == 0) {
                  if ((new_stp->ls_flags & (NFSLCK_LOCK | NFSLCK_UNLOCK)) != 0 &&
                      nfsrv_dolocallocks != 0 && nd->nd_repstat == 0) {
                          getlckret = nfsrv_getlockfile(new_stp->ls_flags, NULL,
                              &lfp, &nfh, 1);
                          if (getlckret == 0)
                                  filestruct_locked = 1;
                  } else
                          getlckret = nfsrv_getlockfile(new_stp->ls_flags, NULL,
                              &lfp, &nfh, 0);
          }
          if (getlckret != 0 && getlckret != -1)
                  reterr = getlckret;
  
          if (filestruct_locked != 0) {
                  LIST_INIT(&lfp->lf_rollback);
                  if ((new_stp->ls_flags & NFSLCK_LOCK)) {
                          /*
                           * For local locking, do the advisory locking now, so
                           * that any conflict can be detected. A failure later
                           * can be rolled back locally. If an error is returned,
                           * struct nfslockfile has been unlocked and any local
                           * locking rolled back.
                           */
                          NFSUNLOCKSTATE();
                          reterr = nfsrv_locallock(vp, lfp,
                              (new_lop->lo_flags & (NFSLCK_READ | NFSLCK_WRITE)),
                              new_lop->lo_first, new_lop->lo_end, cfp, p);
                          NFSLOCKSTATE();
                  }
          }
  
          if (specialid == 0) {
              if (new_stp->ls_flags & NFSLCK_TEST) {
                  /*
                   * RFC 3530 does not list LockT as an op that renews a
                   * lease, but the concensus seems to be that it is ok
                   * for a server to do so.
                   */
                  error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
                      (nfsquad_t)((u_quad_t)0), NULL, p);
  
                  /*
                   * Since NFSERR_EXPIRED, NFSERR_ADMINREVOKED are not valid
                   * error returns for LockT, just go ahead and test for a lock,
                   * since there are no locks for this client, but other locks
                   * can conflict. (ie. same client will always be false)
                   */
                  if (error == NFSERR_EXPIRED || error == NFSERR_ADMINREVOKED)
                      error = 0;
                  lckstp = new_stp;
              } else {
                error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
                  (nfsquad_t)((u_quad_t)0), NULL, p);
                if (error == 0)
                  /*
                   * Look up the stateid
                   */
                  error = nfsrv_getstate(clp, &new_stp->ls_stateid,
                    new_stp->ls_flags, &stp);
                /*
                 * do some sanity checks for an unconfirmed open or a
                 * stateid that refers to the wrong file, for an open stateid
                 */
                if (error == 0 && (stp->ls_flags & NFSLCK_OPEN) &&
                    ((stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM) ||
                     (getlckret == 0 && stp->ls_lfp != lfp)))
                          error = NFSERR_BADSTATEID;
                if (error == 0 &&
                    (stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) &&
                    getlckret == 0 && stp->ls_lfp != lfp)
                          error = NFSERR_BADSTATEID;
  
                /*
                 * If the lockowner stateid doesn't refer to the same file,
                 * I believe that is considered ok, since some clients will
                 * only create a single lockowner and use that for all locks
                 * on all files.
                 * For now, log it as a diagnostic, instead of considering it
                 * a BadStateid.
                 */
                if (error == 0 && (stp->ls_flags &
                    (NFSLCK_OPEN | NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) == 0 &&
                    getlckret == 0 && stp->ls_lfp != lfp) {
  #ifdef DIAGNOSTIC
                    printf("Got a lock statid for different file open\n");
  #endif
                    /*
                    error = NFSERR_BADSTATEID;
                    */
                }
  
                if (error == 0) {
                      if (new_stp->ls_flags & NFSLCK_OPENTOLOCK) {
                          /*
                           * If haslock set, we've already checked the seqid.
                           */
                          if (!haslock) {
                              if (stp->ls_flags & NFSLCK_OPEN)
                                  error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                                      stp->ls_openowner, new_stp->ls_op);
                              else
                                  error = NFSERR_BADSTATEID;
                          }
                          if (!error)
                              nfsrv_getowner(&stp->ls_open, new_stp, &lckstp);
                          if (lckstp)
                              /*
                               * I believe this should be an error, but it
                               * isn't obvious what NFSERR_xxx would be
                               * appropriate, so I'll use NFSERR_INVAL for now.
                               */
                              error = NFSERR_INVAL;
                          else
                              lckstp = new_stp;
                      } else if (new_stp->ls_flags&(NFSLCK_LOCK|NFSLCK_UNLOCK)) {
                          /*
                           * If haslock set, ditto above.
                           */
                          if (!haslock) {
                              if (stp->ls_flags & NFSLCK_OPEN)
                                  error = NFSERR_BADSTATEID;
                              else
                                  error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                                      stp, new_stp->ls_op);
                          }
                          lckstp = stp;
                      } else {
                          lckstp = stp;
                      }
                }
                /*
                 * If the seqid part of the stateid isn't the same, return
                 * NFSERR_OLDSTATEID for cases other than I/O Ops.
                 * For I/O Ops, only return NFSERR_OLDSTATEID if
                 * nfsrv_returnoldstateid is set. (The concensus on the email
                 * list was that most clients would prefer to not receive
                 * NFSERR_OLDSTATEID for I/O Ops, but the RFC suggests that that
                 * is what will happen, so I use the nfsrv_returnoldstateid to
                 * allow for either server configuration.)
                 */
                if (!error && stp->ls_stateid.seqid!=new_stp->ls_stateid.seqid &&
                    (!(new_stp->ls_flags & NFSLCK_CHECK) ||
                     nfsrv_returnoldstateid))
                      error = NFSERR_OLDSTATEID;
              }
          }
  
          /*
           * Now we can check for grace.
           */
          if (!error)
                  error = nfsrv_checkgrace(new_stp->ls_flags);
          if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error &&
                  nfsrv_checkstable(clp))
                  error = NFSERR_NOGRACE;
          /*
           * If we successfully Reclaimed state, note that.
           */
          if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error)
                  nfsrv_markstable(clp);
  
          /*
           * At this point, either error == NFSERR_BADSTATEID or the
           * seqid# has been updated, so we can return any error.
           * If error == 0, there may be an error in:
           *    nd_repstat - Set by the calling function.
           *    reterr - Set above, if getting the nfslockfile structure
           *       or acquiring the local lock failed.
           *    (If both of these are set, nd_repstat should probably be
           *     returned, since that error was detected before this
           *     function call.)
           */
          if (error != 0 || nd->nd_repstat != 0 || reterr != 0) {
                  if (error == 0) {
                          if (nd->nd_repstat != 0)
                                  error = nd->nd_repstat;
                          else
                                  error = reterr;
                  }
                  if (filestruct_locked != 0) {
                          /* Roll back local locks. */
                          NFSUNLOCKSTATE();
                          nfsrv_locallock_rollback(vp, lfp, p);
                          NFSLOCKSTATE();
                          nfsrv_unlocklf(lfp);
                  }
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * Check the nfsrv_getlockfile return.
           * Returned -1 if no structure found.
           */
          if (getlckret == -1) {
                  error = NFSERR_EXPIRED;
                  /*
                   * Called from lockt, so no lock is OK.
                   */
                  if (new_stp->ls_flags & NFSLCK_TEST) {
                          error = 0;
                  } else if (new_stp->ls_flags &
                      (NFSLCK_CHECK | NFSLCK_SETATTR)) {
                          /*
                           * Called to check for a lock, OK if the stateid is all
                           * 1s or all 0s, but there should be an nfsstate
                           * otherwise.
                           * (ie. If there is no open, I'll assume no share
                           *  deny bits.)
                           */
                          if (specialid)
                                  error = 0;
                          else
                                  error = NFSERR_BADSTATEID;
                  }
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * For NFSLCK_CHECK and NFSLCK_LOCK, test for a share conflict.
           * For NFSLCK_CHECK, allow a read if write access is granted,
           * but check for a deny. For NFSLCK_LOCK, require correct access,
           * which implies a conflicting deny can't exist.
           */
          if (new_stp->ls_flags & (NFSLCK_CHECK | NFSLCK_LOCK)) {
              /*
               * Four kinds of state id:
               * - specialid (all 0s or all 1s), only for NFSLCK_CHECK
               * - stateid for an open
               * - stateid for a delegation
               * - stateid for a lock owner
               */
              if (!specialid) {
                  if (stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) {
                      delegation = 1;
                      mystp = stp;
                      nfsrv_delaydelegtimeout(stp);
                  } else if (stp->ls_flags & NFSLCK_OPEN) {
                      mystp = stp;
                  } else {
                      mystp = stp->ls_openstp;
                  }
                  /*
                   * If locking or checking, require correct access
                   * bit set.
                   */
                  if (((new_stp->ls_flags & NFSLCK_LOCK) &&
                       !((new_lop->lo_flags >> NFSLCK_LOCKSHIFT) &
                         mystp->ls_flags & NFSLCK_ACCESSBITS)) ||
                      ((new_stp->ls_flags & (NFSLCK_CHECK|NFSLCK_READACCESS)) ==
                        (NFSLCK_CHECK | NFSLCK_READACCESS) &&
                       !(mystp->ls_flags & NFSLCK_READACCESS)) ||
                      ((new_stp->ls_flags & (NFSLCK_CHECK|NFSLCK_WRITEACCESS)) ==
                        (NFSLCK_CHECK | NFSLCK_WRITEACCESS) &&
                       !(mystp->ls_flags & NFSLCK_WRITEACCESS))) {
                          if (filestruct_locked != 0) {
                                  /* Roll back local locks. */
                                  NFSUNLOCKSTATE();
                                  nfsrv_locallock_rollback(vp, lfp, p);
                                  NFSLOCKSTATE();
                                  nfsrv_unlocklf(lfp);
                          }
                          NFSUNLOCKSTATE();
                          error = NFSERR_OPENMODE;
                          goto out;
                  }
              } else
                  mystp = NULL;
              if ((new_stp->ls_flags & NFSLCK_CHECK) && !delegation) {
                  /*
                   * Check for a conflicting deny bit.
                   */
                  LIST_FOREACH(tstp, &lfp->lf_open, ls_file) {
                      if (tstp != mystp) {
                          bits = tstp->ls_flags;
                          bits >>= NFSLCK_SHIFT;
                          if (new_stp->ls_flags & bits & NFSLCK_ACCESSBITS) {
                              ret = nfsrv_clientconflict(tstp->ls_clp, &haslock,
                                  vp, p);
                              if (ret == 1) {
                                  /*
                                  * nfsrv_clientconflict unlocks state
                                   * when it returns non-zero.
                                   */
                                  lckstp = NULL;
                                  goto tryagain;
                              }
                              if (ret == 0)
                                  NFSUNLOCKSTATE();
                              if (ret == 2)
                                  error = NFSERR_PERM;
                              else
                                  error = NFSERR_OPENMODE;
                              goto out;
                          }
                      }
                  }
  
                  /* We're outta here */
                  NFSUNLOCKSTATE();
                  goto out;
              }
          }
  
          /*
           * For setattr, just get rid of all the Delegations for other clients.
           */
          if (new_stp->ls_flags & NFSLCK_SETATTR) {
                  ret = nfsrv_cleandeleg(vp, lfp, clp, &haslock, p);
                  if (ret) {
                          /*
                           * nfsrv_cleandeleg() unlocks state when it
                           * returns non-zero.
                           */
                          if (ret == -1) {
                                  lckstp = NULL;
                                  goto tryagain;
                          }
                          error = ret;
                          goto out;
                  }
                  if (!(new_stp->ls_flags & NFSLCK_CHECK) ||
                      (LIST_EMPTY(&lfp->lf_open) && LIST_EMPTY(&lfp->lf_lock) &&
                       LIST_EMPTY(&lfp->lf_deleg))) {
                          NFSUNLOCKSTATE();
                          goto out;
                  }
          }
  
          /*
           * Check for a conflicting delegation. If one is found, call
           * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
           * been set yet, it will get the lock. Otherwise, it will recall
           * the delegation. Then, we try try again...
           * I currently believe the conflict algorithm to be:
           * For Lock Ops (Lock/LockT/LockU)
           * - there is a conflict iff a different client has a write delegation
           * For Reading (Read Op)
           * - there is a conflict iff a different client has a write delegation
           *   (the specialids are always a different client)
           * For Writing (Write/Setattr of size)
           * - there is a conflict if a different client has any delegation
           * - there is a conflict if the same client has a read delegation
           *   (I don't understand why this isn't allowed, but that seems to be
           *    the current concensus?)
           */
          tstp = LIST_FIRST(&lfp->lf_deleg);
          while (tstp != LIST_END(&lfp->lf_deleg)) {
              nstp = LIST_NEXT(tstp, ls_file);
              if ((((new_stp->ls_flags&(NFSLCK_LOCK|NFSLCK_UNLOCK|NFSLCK_TEST))||
                   ((new_stp->ls_flags & NFSLCK_CHECK) &&
                    (new_lop->lo_flags & NFSLCK_READ))) &&
                    clp != tstp->ls_clp &&
                   (tstp->ls_flags & NFSLCK_DELEGWRITE)) ||
                   ((new_stp->ls_flags & NFSLCK_CHECK) &&
                     (new_lop->lo_flags & NFSLCK_WRITE) &&
                    (clp != tstp->ls_clp ||
                     (tstp->ls_flags & NFSLCK_DELEGREAD)))) {
                  if (filestruct_locked != 0) {
                          /* Roll back local locks. */
                          NFSUNLOCKSTATE();
                          nfsrv_locallock_rollback(vp, lfp, p);
                          NFSLOCKSTATE();
                          nfsrv_unlocklf(lfp);
                  }
                  ret = nfsrv_delegconflict(tstp, &haslock, p, vp);
                  if (ret) {
                      /*
                       * nfsrv_delegconflict unlocks state when it
                       * returns non-zero, which it always does.
                       */
                      if (other_lop) {
                          FREE((caddr_t)other_lop, M_NFSDLOCK);
                          other_lop = NULL;
                      }
                      if (ret == -1) {
                          lckstp = NULL;
                          goto tryagain;
                      }
                      error = ret;
                      goto out;
                  }
                  /* Never gets here. */
              }
              tstp = nstp;
          }
  
          /*
           * Handle the unlock case by calling nfsrv_updatelock().
           * (Should I have done some access checking above for unlock? For now,
           *  just let it happen.)
           */
          if (new_stp->ls_flags & NFSLCK_UNLOCK) {
                  first = new_lop->lo_first;
                  end = new_lop->lo_end;
                  nfsrv_updatelock(stp, new_lopp, &other_lop, lfp);
                  stateidp->seqid = ++(stp->ls_stateid.seqid);
                  stateidp->other[0] = stp->ls_stateid.other[0];
                  stateidp->other[1] = stp->ls_stateid.other[1];
                  stateidp->other[2] = stp->ls_stateid.other[2];
                  if (filestruct_locked != 0) {
                          NFSUNLOCKSTATE();
                          /* Update the local locks. */
                          nfsrv_localunlock(vp, lfp, first, end, p);
                          NFSLOCKSTATE();
                          nfsrv_unlocklf(lfp);
                  }
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * Search for a conflicting lock. A lock conflicts if:
           * - the lock range overlaps and
           * - at least one lock is a write lock and
           * - it is not owned by the same lock owner
           */
          if (!delegation) {
            LIST_FOREACH(lop, &lfp->lf_lock, lo_lckfile) {
              if (new_lop->lo_end > lop->lo_first &&
                  new_lop->lo_first < lop->lo_end &&
                  (new_lop->lo_flags == NFSLCK_WRITE ||
                   lop->lo_flags == NFSLCK_WRITE) &&
                  lckstp != lop->lo_stp &&
                  (clp != lop->lo_stp->ls_clp ||
                   lckstp->ls_ownerlen != lop->lo_stp->ls_ownerlen ||
                   NFSBCMP(lckstp->ls_owner, lop->lo_stp->ls_owner,
                      lckstp->ls_ownerlen))) {
                  if (other_lop) {
                      FREE((caddr_t)other_lop, M_NFSDLOCK);
                      other_lop = NULL;
                  }
                  ret = nfsrv_clientconflict(lop->lo_stp->ls_clp,&haslock,vp,p);
                  if (ret == 1) {
                      if (filestruct_locked != 0) {
                          /* Roll back local locks. */
                          nfsrv_locallock_rollback(vp, lfp, p);
                          NFSLOCKSTATE();
                          nfsrv_unlocklf(lfp);
                          NFSUNLOCKSTATE();
                      }
                      /*
                       * nfsrv_clientconflict() unlocks state when it
                       * returns non-zero.
                       */
                      lckstp = NULL;
                      goto tryagain;
                  }
                  /*
                   * Found a conflicting lock, so record the conflict and
                   * return the error.
                   */
                  if (cfp != NULL && ret == 0) {
                      cfp->cl_clientid.lval[0]=lop->lo_stp->ls_stateid.other[0];
                      cfp->cl_clientid.lval[1]=lop->lo_stp->ls_stateid.other[1];
                      cfp->cl_first = lop->lo_first;
                      cfp->cl_end = lop->lo_end;
                      cfp->cl_flags = lop->lo_flags;
                      cfp->cl_ownerlen = lop->lo_stp->ls_ownerlen;
                      NFSBCOPY(lop->lo_stp->ls_owner, cfp->cl_owner,
                          cfp->cl_ownerlen);
                  }
                  if (ret == 2)
                      error = NFSERR_PERM;
                  else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                      error = NFSERR_RECLAIMCONFLICT;
                  else if (new_stp->ls_flags & NFSLCK_CHECK)
                      error = NFSERR_LOCKED;
                  else
                      error = NFSERR_DENIED;
                  if (filestruct_locked != 0 && ret == 0) {
                          /* Roll back local locks. */
                          NFSUNLOCKSTATE();
                          nfsrv_locallock_rollback(vp, lfp, p);
                          NFSLOCKSTATE();
                          nfsrv_unlocklf(lfp);
                  }
                  if (ret == 0)
                          NFSUNLOCKSTATE();
                  goto out;
              }
            }
          }
  
          /*
           * We only get here if there was no lock that conflicted.
           */
          if (new_stp->ls_flags & (NFSLCK_TEST | NFSLCK_CHECK)) {
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * We only get here when we are creating or modifying a lock.
           * There are two variants:
           * - exist_lock_owner where lock_owner exists
           * - open_to_lock_owner with new lock_owner
           */
          first = new_lop->lo_first;
          end = new_lop->lo_end;
          lock_flags = new_lop->lo_flags;
          if (!(new_stp->ls_flags & NFSLCK_OPENTOLOCK)) {
                  nfsrv_updatelock(lckstp, new_lopp, &other_lop, lfp);
                  stateidp->seqid = ++(lckstp->ls_stateid.seqid);
                  stateidp->other[0] = lckstp->ls_stateid.other[0];
                  stateidp->other[1] = lckstp->ls_stateid.other[1];
                  stateidp->other[2] = lckstp->ls_stateid.other[2];
          } else {
                  /*
                   * The new open_to_lock_owner case.
                   * Link the new nfsstate into the lists.
                   */
                  new_stp->ls_seq = new_stp->ls_opentolockseq;
                  nfsrvd_refcache(new_stp->ls_op);
                  stateidp->seqid = new_stp->ls_stateid.seqid = 1;
                  stateidp->other[0] = new_stp->ls_stateid.other[0] =
                      clp->lc_clientid.lval[0];
                  stateidp->other[1] = new_stp->ls_stateid.other[1] =
                      clp->lc_clientid.lval[1];
                  stateidp->other[2] = new_stp->ls_stateid.other[2] =
                      nfsrv_nextstateindex(clp);
                  new_stp->ls_clp = clp;
                  LIST_INIT(&new_stp->ls_lock);
                  new_stp->ls_openstp = stp;
                  new_stp->ls_lfp = lfp;
                  nfsrv_insertlock(new_lop, (struct nfslock *)new_stp, new_stp,
                      lfp);
                  LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_stp->ls_stateid),
                      new_stp, ls_hash);
                  LIST_INSERT_HEAD(&stp->ls_open, new_stp, ls_list);
                  *new_lopp = NULL;
                  *new_stpp = NULL;
                  newnfsstats.srvlockowners++;
                  nfsrv_openpluslock++;
          }
          if (filestruct_locked != 0) {
                  NFSUNLOCKSTATE();
                  nfsrv_locallock_commit(lfp, lock_flags, first, end);
                  NFSLOCKSTATE();
                  nfsrv_unlocklf(lfp);
          }
          NFSUNLOCKSTATE();
  
  out:
          if (haslock) {
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                  NFSUNLOCKV4ROOTMUTEX();
          }
          if (other_lop)
                  FREE((caddr_t)other_lop, M_NFSDLOCK);
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Check for state errors for Open.
   * repstat is passed back out as an error if more critical errors
   * are not detected.
   */
  APPLESTATIC int
  nfsrv_opencheck(nfsquad_t clientid, nfsv4stateid_t *stateidp,
      struct nfsstate *new_stp, vnode_t vp, struct nfsrv_descript *nd,
      NFSPROC_T *p, int repstat)
  {
          struct nfsstate *stp, *nstp;
          struct nfsclient *clp;
          struct nfsstate *ownerstp;
          struct nfslockfile *lfp, *new_lfp;
          int error = 0, haslock = 0, ret, readonly = 0, getfhret = 0;
  
          if ((new_stp->ls_flags & NFSLCK_SHAREBITS) == NFSLCK_READACCESS)
                  readonly = 1;
          /*
           * Check for restart conditions (client and server).
           */
          error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
                  &new_stp->ls_stateid, 0);
          if (error)
                  goto out;
  
          /*
           * Check for state resource limit exceeded.
           * Technically this should be SMP protected, but the worst
           * case error is "out by one or two" on the count when it
           * returns NFSERR_RESOURCE and the limit is just a rather
           * arbitrary high water mark, so no harm is done.
           */
          if (nfsrv_openpluslock > NFSRV_V4STATELIMIT) {
                  error = NFSERR_RESOURCE;
                  goto out;
          }
  
  tryagain:
          MALLOC(new_lfp, struct nfslockfile *, sizeof (struct nfslockfile),
              M_NFSDLOCKFILE, M_WAITOK);
          if (vp)
                  getfhret = nfsrv_getlockfh(vp, new_stp->ls_flags, &new_lfp,
                      NULL, p);
          NFSLOCKSTATE();
          /*
           * Get the nfsclient structure.
           */
          error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
              (nfsquad_t)((u_quad_t)0), NULL, p);
  
          /*
           * Look up the open owner. See if it needs confirmation and
           * check the seq#, as required.
           */
          if (!error)
                  nfsrv_getowner(&clp->lc_open, new_stp, &ownerstp);
  
          if (!error && ownerstp) {
                  error = nfsrv_checkseqid(nd, new_stp->ls_seq, ownerstp,
                      new_stp->ls_op);
                  /*
                   * If the OpenOwner hasn't been confirmed, assume the
                   * old one was a replay and this one is ok.
                   * See: RFC3530 Sec. 14.2.18.
                   */
                  if (error == NFSERR_BADSEQID &&
                      (ownerstp->ls_flags & NFSLCK_NEEDSCONFIRM))
                          error = 0;
          }
  
          /*
           * Check for grace.
           */
          if (!error)
                  error = nfsrv_checkgrace(new_stp->ls_flags);
          if ((new_stp->ls_flags & NFSLCK_RECLAIM) && !error &&
                  nfsrv_checkstable(clp))
                  error = NFSERR_NOGRACE;
  
          /*
           * If none of the above errors occurred, let repstat be
           * returned.
           */
          if (repstat && !error)
                  error = repstat;
          if (error) {
                  NFSUNLOCKSTATE();
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  free((caddr_t)new_lfp, M_NFSDLOCKFILE);
                  goto out;
          }
  
          /*
           * If vp == NULL, the file doesn't exist yet, so return ok.
           * (This always happens on the first pass, so haslock must be 0.)
           */
          if (vp == NULL) {
                  NFSUNLOCKSTATE();
                  FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
                  goto out;
          }
  
          /*
           * Get the structure for the underlying file.
           */
          if (getfhret)
                  error = getfhret;
          else
                  error = nfsrv_getlockfile(new_stp->ls_flags, &new_lfp, &lfp,
                      NULL, 0);
          if (new_lfp)
                  FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
          if (error) {
                  NFSUNLOCKSTATE();
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  goto out;
          }
  
          /*
           * Search for a conflicting open/share.
           */
          if (new_stp->ls_flags & NFSLCK_DELEGCUR) {
              /*
               * For Delegate_Cur, search for the matching Delegation,
               * which indicates no conflict.
               * An old delegation should have been recovered by the
               * client doing a Claim_DELEGATE_Prev, so I won't let
               * it match and return NFSERR_EXPIRED. Should I let it
               * match?
               */
              LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                  if (!(stp->ls_flags & NFSLCK_OLDDELEG) &&
                      stateidp->seqid == stp->ls_stateid.seqid &&
                      !NFSBCMP(stateidp->other, stp->ls_stateid.other,
                            NFSX_STATEIDOTHER))
                          break;
              }
              if (stp == LIST_END(&lfp->lf_deleg) ||
                  ((new_stp->ls_flags & NFSLCK_WRITEACCESS) &&
                   (stp->ls_flags & NFSLCK_DELEGREAD))) {
                  NFSUNLOCKSTATE();
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  error = NFSERR_EXPIRED;
                  goto out;
              }
          }
  
          /*
           * Check for access/deny bit conflicts. I check for the same
           * owner as well, in case the client didn't bother.
           */
          LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                  if (!(new_stp->ls_flags & NFSLCK_DELEGCUR) &&
                      (((new_stp->ls_flags & NFSLCK_ACCESSBITS) &
                        ((stp->ls_flags>>NFSLCK_SHIFT) & NFSLCK_ACCESSBITS))||
                       ((stp->ls_flags & NFSLCK_ACCESSBITS) &
                        ((new_stp->ls_flags>>NFSLCK_SHIFT)&NFSLCK_ACCESSBITS)))){
                          ret = nfsrv_clientconflict(stp->ls_clp,&haslock,vp,p);
                          if (ret == 1) {
                                  /*
                                   * nfsrv_clientconflict() unlocks
                                   * state when it returns non-zero.
                                   */
                                  goto tryagain;
                          }
                          if (ret == 2)
                                  error = NFSERR_PERM;
                          else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                                  error = NFSERR_RECLAIMCONFLICT;
                          else
                                  error = NFSERR_SHAREDENIED;
                          if (ret == 0)
                                  NFSUNLOCKSTATE();
                          if (haslock) {
                                  NFSLOCKV4ROOTMUTEX();
                                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                                  NFSUNLOCKV4ROOTMUTEX();
                          }
                          goto out;
                  }
          }
  
          /*
           * Check for a conflicting delegation. If one is found, call
           * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
           * been set yet, it will get the lock. Otherwise, it will recall
           * the delegation. Then, we try try again...
           * (If NFSLCK_DELEGCUR is set, it has a delegation, so there
           *  isn't a conflict.)
           * I currently believe the conflict algorithm to be:
           * For Open with Read Access and Deny None
           * - there is a conflict iff a different client has a write delegation
           * For Open with other Write Access or any Deny except None
           * - there is a conflict if a different client has any delegation
           * - there is a conflict if the same client has a read delegation
           *   (The current concensus is that this last case should be
           *    considered a conflict since the client with a read delegation
           *    could have done an Open with ReadAccess and WriteDeny
           *    locally and then not have checked for the WriteDeny.)
           * Don't check for a Reclaim, since that will be dealt with
           * by nfsrv_openctrl().
           */
          if (!(new_stp->ls_flags &
                  (NFSLCK_DELEGPREV | NFSLCK_DELEGCUR | NFSLCK_RECLAIM))) {
              stp = LIST_FIRST(&lfp->lf_deleg);
              while (stp != LIST_END(&lfp->lf_deleg)) {
                  nstp = LIST_NEXT(stp, ls_file);
                  if ((readonly && stp->ls_clp != clp &&
                         (stp->ls_flags & NFSLCK_DELEGWRITE)) ||
                      (!readonly && (stp->ls_clp != clp ||
                           (stp->ls_flags & NFSLCK_DELEGREAD)))) {
                          ret = nfsrv_delegconflict(stp, &haslock, p, vp);
                          if (ret) {
                              /*
                               * nfsrv_delegconflict() unlocks state
                               * when it returns non-zero.
                               */
                              if (ret == -1)
                                  goto tryagain;
                              error = ret;
                              goto out;
                          }
                  }
                  stp = nstp;
              }
          }
          NFSUNLOCKSTATE();
          if (haslock) {
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                  NFSUNLOCKV4ROOTMUTEX();
          }
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Open control function to create/update open state for an open.
   */
  APPLESTATIC int
  nfsrv_openctrl(struct nfsrv_descript *nd, vnode_t vp,
      struct nfsstate **new_stpp, nfsquad_t clientid, nfsv4stateid_t *stateidp,
      nfsv4stateid_t *delegstateidp, u_int32_t *rflagsp, struct nfsexstuff *exp,
      NFSPROC_T *p, u_quad_t filerev)
  {
          struct nfsstate *new_stp = *new_stpp;
          struct nfsstate *stp, *nstp;
          struct nfsstate *openstp = NULL, *new_open, *ownerstp, *new_deleg;
          struct nfslockfile *lfp, *new_lfp;
          struct nfsclient *clp;
          int error = 0, haslock = 0, ret, delegate = 1, writedeleg = 1;
          int readonly = 0, cbret = 1, getfhret = 0;
  
          if ((new_stp->ls_flags & NFSLCK_SHAREBITS) == NFSLCK_READACCESS)
                  readonly = 1;
          /*
           * Check for restart conditions (client and server).
           * (Paranoia, should have been detected by nfsrv_opencheck().)
           * If an error does show up, return NFSERR_EXPIRED, since the
           * the seqid# has already been incremented.
           */
          error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
              &new_stp->ls_stateid, 0);
          if (error) {
                  printf("Nfsd: openctrl unexpected restart err=%d\n",
                      error);
                  error = NFSERR_EXPIRED;
                  goto out;
          }
  
  tryagain:
          MALLOC(new_lfp, struct nfslockfile *, sizeof (struct nfslockfile),
              M_NFSDLOCKFILE, M_WAITOK);
          MALLOC(new_open, struct nfsstate *, sizeof (struct nfsstate),
              M_NFSDSTATE, M_WAITOK);
          MALLOC(new_deleg, struct nfsstate *, sizeof (struct nfsstate),
              M_NFSDSTATE, M_WAITOK);
          getfhret = nfsrv_getlockfh(vp, new_stp->ls_flags, &new_lfp,
              NULL, p);
          NFSLOCKSTATE();
          /*
           * Get the client structure. Since the linked lists could be changed
           * by other nfsd processes if this process does a tsleep(), one of
           * two things must be done.
           * 1 - don't tsleep()
           * or
           * 2 - get the nfsv4_lock() { indicated by haslock == 1 }
           *     before using the lists, since this lock stops the other
           *     nfsd. This should only be used for rare cases, since it
           *     essentially single threads the nfsd.
           *     At this time, it is only done for cases where the stable
           *     storage file must be written prior to completion of state
           *     expiration.
           */
          error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
              (nfsquad_t)((u_quad_t)0), NULL, p);
          if (!error && (clp->lc_flags & LCL_NEEDSCBNULL) &&
              clp->lc_program) {
                  /*
                   * This happens on the first open for a client
                   * that supports callbacks.
                   */
                  NFSUNLOCKSTATE();
                  /*
                   * Although nfsrv_docallback() will sleep, clp won't
                   * go away, since they are only removed when the
                   * nfsv4_lock() has blocked the nfsd threads. The
                   * fields in clp can change, but having multiple
                   * threads do this Null callback RPC should be
                   * harmless.
                   */
                  cbret = nfsrv_docallback(clp, NFSV4PROC_CBNULL,
                      NULL, 0, NULL, NULL, NULL, p);
                  NFSLOCKSTATE();
                  clp->lc_flags &= ~LCL_NEEDSCBNULL;
                  if (!cbret)
                          clp->lc_flags |= LCL_CALLBACKSON;
          }
  
          /*
           * Look up the open owner. See if it needs confirmation and
           * check the seq#, as required.
           */
          if (!error)
                  nfsrv_getowner(&clp->lc_open, new_stp, &ownerstp);
  
          if (error) {
                  NFSUNLOCKSTATE();
                  printf("Nfsd: openctrl unexpected state err=%d\n",
                          error);
                  free((caddr_t)new_lfp, M_NFSDLOCKFILE);
                  free((caddr_t)new_open, M_NFSDSTATE);
                  free((caddr_t)new_deleg, M_NFSDSTATE);
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  error = NFSERR_EXPIRED;
                  goto out;
          }
  
          if (new_stp->ls_flags & NFSLCK_RECLAIM)
                  nfsrv_markstable(clp);
  
          /*
           * Get the structure for the underlying file.
           */
          if (getfhret)
                  error = getfhret;
          else
                  error = nfsrv_getlockfile(new_stp->ls_flags, &new_lfp, &lfp,
                      NULL, 0);
          if (new_lfp)
                  FREE((caddr_t)new_lfp, M_NFSDLOCKFILE);
          if (error) {
                  NFSUNLOCKSTATE();
                  printf("Nfsd openctrl unexpected getlockfile err=%d\n",
                      error);
                  free((caddr_t)new_open, M_NFSDSTATE);
                  free((caddr_t)new_deleg, M_NFSDSTATE);
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  goto out;
          }
  
          /*
           * Search for a conflicting open/share.
           */
          if (new_stp->ls_flags & NFSLCK_DELEGCUR) {
              /*
               * For Delegate_Cur, search for the matching Delegation,
               * which indicates no conflict.
               * An old delegation should have been recovered by the
               * client doing a Claim_DELEGATE_Prev, so I won't let
               * it match and return NFSERR_EXPIRED. Should I let it
               * match?
               */
              LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                  if (!(stp->ls_flags & NFSLCK_OLDDELEG) &&
                      stateidp->seqid == stp->ls_stateid.seqid &&
                      !NFSBCMP(stateidp->other, stp->ls_stateid.other,
                          NFSX_STATEIDOTHER))
                          break;
              }
              if (stp == LIST_END(&lfp->lf_deleg) ||
                  ((new_stp->ls_flags & NFSLCK_WRITEACCESS) &&
                   (stp->ls_flags & NFSLCK_DELEGREAD))) {
                  NFSUNLOCKSTATE();
                  printf("Nfsd openctrl unexpected expiry\n");
                  free((caddr_t)new_open, M_NFSDSTATE);
                  free((caddr_t)new_deleg, M_NFSDSTATE);
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  error = NFSERR_EXPIRED;
                  goto out;
              }
  
              /*
               * Don't issue a Delegation, since one already exists and
               * delay delegation timeout, as required.
               */
              delegate = 0;
              nfsrv_delaydelegtimeout(stp);
          }
  
          /*
           * Check for access/deny bit conflicts. I also check for the
           * same owner, since the client might not have bothered to check.
           * Also, note an open for the same file and owner, if found,
           * which is all we do here for Delegate_Cur, since conflict
           * checking is already done.
           */
          LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                  if (ownerstp && stp->ls_openowner == ownerstp)
                          openstp = stp;
                  if (!(new_stp->ls_flags & NFSLCK_DELEGCUR)) {
                      /*
                       * If another client has the file open, the only
                       * delegation that can be issued is a Read delegation
                       * and only if it is a Read open with Deny none.
                       */
                      if (clp != stp->ls_clp) {
                          if ((stp->ls_flags & NFSLCK_SHAREBITS) ==
                              NFSLCK_READACCESS)
                              writedeleg = 0;
                          else
                              delegate = 0;
                      }
                      if(((new_stp->ls_flags & NFSLCK_ACCESSBITS) &
                          ((stp->ls_flags>>NFSLCK_SHIFT) & NFSLCK_ACCESSBITS))||
                         ((stp->ls_flags & NFSLCK_ACCESSBITS) &
                          ((new_stp->ls_flags>>NFSLCK_SHIFT)&NFSLCK_ACCESSBITS))){
                          ret = nfsrv_clientconflict(stp->ls_clp,&haslock,vp,p);
                          if (ret == 1) {
                                  /*
                                   * nfsrv_clientconflict() unlocks state
                                   * when it returns non-zero.
                                   */
                                  free((caddr_t)new_open, M_NFSDSTATE);
                                  free((caddr_t)new_deleg, M_NFSDSTATE);
                                  openstp = NULL;
                                  goto tryagain;
                          }
                          if (ret == 2)
                                  error = NFSERR_PERM;
                          else if (new_stp->ls_flags & NFSLCK_RECLAIM)
                                  error = NFSERR_RECLAIMCONFLICT;
                          else
                                  error = NFSERR_SHAREDENIED;
                          if (ret == 0)
                                  NFSUNLOCKSTATE();
                          if (haslock) {
                                  NFSLOCKV4ROOTMUTEX();
                                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                                  NFSUNLOCKV4ROOTMUTEX();
                          }
                          free((caddr_t)new_open, M_NFSDSTATE);
                          free((caddr_t)new_deleg, M_NFSDSTATE);
                          printf("nfsd openctrl unexpected client cnfl\n");
                          goto out;
                      }
                  }
          }
  
          /*
           * Check for a conflicting delegation. If one is found, call
           * nfsrv_delegconflict() to handle it. If the v4root lock hasn't
           * been set yet, it will get the lock. Otherwise, it will recall
           * the delegation. Then, we try try again...
           * (If NFSLCK_DELEGCUR is set, it has a delegation, so there
           *  isn't a conflict.)
           * I currently believe the conflict algorithm to be:
           * For Open with Read Access and Deny None
           * - there is a conflict iff a different client has a write delegation
           * For Open with other Write Access or any Deny except None
           * - there is a conflict if a different client has any delegation
           * - there is a conflict if the same client has a read delegation
           *   (The current concensus is that this last case should be
           *    considered a conflict since the client with a read delegation
           *    could have done an Open with ReadAccess and WriteDeny
           *    locally and then not have checked for the WriteDeny.)
           */
          if (!(new_stp->ls_flags & (NFSLCK_DELEGPREV | NFSLCK_DELEGCUR))) {
              stp = LIST_FIRST(&lfp->lf_deleg);
              while (stp != LIST_END(&lfp->lf_deleg)) {
                  nstp = LIST_NEXT(stp, ls_file);
                  if (stp->ls_clp != clp && (stp->ls_flags & NFSLCK_DELEGREAD))
                          writedeleg = 0;
                  else
                          delegate = 0;
                  if ((readonly && stp->ls_clp != clp &&
                         (stp->ls_flags & NFSLCK_DELEGWRITE)) ||
                      (!readonly && (stp->ls_clp != clp ||
                           (stp->ls_flags & NFSLCK_DELEGREAD)))) {
                      if (new_stp->ls_flags & NFSLCK_RECLAIM) {
                          delegate = 2;
                      } else {
                          ret = nfsrv_delegconflict(stp, &haslock, p, vp);
                          if (ret) {
                              /*
                               * nfsrv_delegconflict() unlocks state
                               * when it returns non-zero.
                               */
                              printf("Nfsd openctrl unexpected deleg cnfl\n");
                              free((caddr_t)new_open, M_NFSDSTATE);
                              free((caddr_t)new_deleg, M_NFSDSTATE);
                              if (ret == -1) {
                                  openstp = NULL;
                                  goto tryagain;
                              }
                              error = ret;
                              goto out;
                          }
                      }
                  }
                  stp = nstp;
              }
          }
  
          /*
           * We only get here if there was no open that conflicted.
           * If an open for the owner exists, or in the access/deny bits.
           * Otherwise it is a new open. If the open_owner hasn't been
           * confirmed, replace the open with the new one needing confirmation,
           * otherwise add the open.
           */
          if (new_stp->ls_flags & NFSLCK_DELEGPREV) {
              /*
               * Handle NFSLCK_DELEGPREV by searching the old delegations for
               * a match. If found, just move the old delegation to the current
               * delegation list and issue open. If not found, return
               * NFSERR_EXPIRED.
               */
              LIST_FOREACH(stp, &clp->lc_olddeleg, ls_list) {
                  if (stp->ls_lfp == lfp) {
                      /* Found it */
                      if (stp->ls_clp != clp)
                          panic("olddeleg clp");
                      LIST_REMOVE(stp, ls_list);
                      LIST_REMOVE(stp, ls_hash);
                      stp->ls_flags &= ~NFSLCK_OLDDELEG;
                      stp->ls_stateid.seqid = delegstateidp->seqid = 0;
                      stp->ls_stateid.other[0] = delegstateidp->other[0] =
                          clp->lc_clientid.lval[0];
                      stp->ls_stateid.other[1] = delegstateidp->other[1] =
                          clp->lc_clientid.lval[1];
                      stp->ls_stateid.other[2] = delegstateidp->other[2] =
                          nfsrv_nextstateindex(clp);
                      stp->ls_compref = nd->nd_compref;
                      LIST_INSERT_HEAD(&clp->lc_deleg, stp, ls_list);
                      LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                          stp->ls_stateid), stp, ls_hash);
                      if (stp->ls_flags & NFSLCK_DELEGWRITE)
                          *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                      else
                          *rflagsp |= NFSV4OPEN_READDELEGATE;
                      clp->lc_delegtime = NFSD_MONOSEC +
                          nfsrv_lease + NFSRV_LEASEDELTA;
  
                      /*
                       * Now, do the associated open.
                       */
                      new_open->ls_stateid.seqid = 0;
                      new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                      new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                      new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                      new_open->ls_flags = (new_stp->ls_flags&NFSLCK_DENYBITS)|
                          NFSLCK_OPEN;
                      if (stp->ls_flags & NFSLCK_DELEGWRITE)
                          new_open->ls_flags |= (NFSLCK_READACCESS |
                              NFSLCK_WRITEACCESS);
                      else
                          new_open->ls_flags |= NFSLCK_READACCESS;
                      new_open->ls_uid = new_stp->ls_uid;
                      new_open->ls_lfp = lfp;
                      new_open->ls_clp = clp;
                      LIST_INIT(&new_open->ls_open);
                      LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                      LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                          new_open, ls_hash);
                      /*
                       * and handle the open owner
                       */
                      if (ownerstp) {
                          new_open->ls_openowner = ownerstp;
                          LIST_INSERT_HEAD(&ownerstp->ls_open,new_open,ls_list);
                      } else {
                          new_open->ls_openowner = new_stp;
                          new_stp->ls_flags = 0;
                          nfsrvd_refcache(new_stp->ls_op);
                          new_stp->ls_noopens = 0;
                          LIST_INIT(&new_stp->ls_open);
                          LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                          LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                          *new_stpp = NULL;
                          newnfsstats.srvopenowners++;
                          nfsrv_openpluslock++;
                      }
                      openstp = new_open;
                      new_open = NULL;
                      newnfsstats.srvopens++;
                      nfsrv_openpluslock++;
                      break;
                  }
              }
              if (stp == LIST_END(&clp->lc_olddeleg))
                  error = NFSERR_EXPIRED;
          } else if (new_stp->ls_flags & (NFSLCK_DELEGREAD | NFSLCK_DELEGWRITE)) {
              /*
               * Scan to see that no delegation for this client and file
               * doesn't already exist.
               * There also shouldn't yet be an Open for this file and
               * openowner.
               */
              LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                  if (stp->ls_clp == clp)
                      break;
              }
              if (stp == LIST_END(&lfp->lf_deleg) && openstp == NULL) {
                  /*
                   * This is the Claim_Previous case with a delegation
                   * type != Delegate_None.
                   */
                  /*
                   * First, add the delegation. (Although we must issue the
                   * delegation, we can also ask for an immediate return.)
                   */
                  new_deleg->ls_stateid.seqid = delegstateidp->seqid = 0;
                  new_deleg->ls_stateid.other[0] = delegstateidp->other[0] =
                      clp->lc_clientid.lval[0];
                  new_deleg->ls_stateid.other[1] = delegstateidp->other[1] =
                      clp->lc_clientid.lval[1];
                  new_deleg->ls_stateid.other[2] = delegstateidp->other[2] =
                      nfsrv_nextstateindex(clp);
                  if (new_stp->ls_flags & NFSLCK_DELEGWRITE) {
                      new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                          NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                      *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                  } else {
                      new_deleg->ls_flags = (NFSLCK_DELEGREAD |
                          NFSLCK_READACCESS);
                      *rflagsp |= NFSV4OPEN_READDELEGATE;
                  }
                  new_deleg->ls_uid = new_stp->ls_uid;
                  new_deleg->ls_lfp = lfp;
                  new_deleg->ls_clp = clp;
                  new_deleg->ls_filerev = filerev;
                  new_deleg->ls_compref = nd->nd_compref;
                  LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                  LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                      new_deleg->ls_stateid), new_deleg, ls_hash);
                  LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                  new_deleg = NULL;
                  if (delegate == 2 || nfsrv_issuedelegs == 0 ||
                      (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) !=
                       LCL_CALLBACKSON ||
                      NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt) ||
                      !NFSVNO_DELEGOK(vp))
                      *rflagsp |= NFSV4OPEN_RECALL;
                  newnfsstats.srvdelegates++;
                  nfsrv_openpluslock++;
                  nfsrv_delegatecnt++;
  
                  /*
                   * Now, do the associated open.
                   */
                  new_open->ls_stateid.seqid = 0;
                  new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                  new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                  new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                  new_open->ls_flags = (new_stp->ls_flags & NFSLCK_DENYBITS) |
                      NFSLCK_OPEN;
                  if (new_stp->ls_flags & NFSLCK_DELEGWRITE)
                          new_open->ls_flags |= (NFSLCK_READACCESS |
                              NFSLCK_WRITEACCESS);
                  else
                          new_open->ls_flags |= NFSLCK_READACCESS;
                  new_open->ls_uid = new_stp->ls_uid;
                  new_open->ls_lfp = lfp;
                  new_open->ls_clp = clp;
                  LIST_INIT(&new_open->ls_open);
                  LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                  LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                     new_open, ls_hash);
                  /*
                   * and handle the open owner
                   */
                  if (ownerstp) {
                      new_open->ls_openowner = ownerstp;
                      LIST_INSERT_HEAD(&ownerstp->ls_open, new_open, ls_list);
                  } else {
                      new_open->ls_openowner = new_stp;
                      new_stp->ls_flags = 0;
                      nfsrvd_refcache(new_stp->ls_op);
                      new_stp->ls_noopens = 0;
                      LIST_INIT(&new_stp->ls_open);
                      LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                      LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                      *new_stpp = NULL;
                      newnfsstats.srvopenowners++;
                      nfsrv_openpluslock++;
                  }
                  openstp = new_open;
                  new_open = NULL;
                  newnfsstats.srvopens++;
                  nfsrv_openpluslock++;
              } else {
                  error = NFSERR_RECLAIMCONFLICT;
              }
          } else if (ownerstp) {
                  if (ownerstp->ls_flags & NFSLCK_NEEDSCONFIRM) {
                      /* Replace the open */
                      if (ownerstp->ls_op)
                          nfsrvd_derefcache(ownerstp->ls_op);
                      ownerstp->ls_op = new_stp->ls_op;
                      nfsrvd_refcache(ownerstp->ls_op);
                      ownerstp->ls_seq = new_stp->ls_seq;
                      *rflagsp |= NFSV4OPEN_RESULTCONFIRM;
                      stp = LIST_FIRST(&ownerstp->ls_open);
                      stp->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS) |
                          NFSLCK_OPEN;
                      stp->ls_stateid.seqid = 0;
                      stp->ls_uid = new_stp->ls_uid;
                      if (lfp != stp->ls_lfp) {
                          LIST_REMOVE(stp, ls_file);
                          LIST_INSERT_HEAD(&lfp->lf_open, stp, ls_file);
                          stp->ls_lfp = lfp;
                      }
                      openstp = stp;
                  } else if (openstp) {
                      openstp->ls_flags |= (new_stp->ls_flags & NFSLCK_SHAREBITS);
                      openstp->ls_stateid.seqid++;
  
                      /*
                       * This is where we can choose to issue a delegation.
                       */
                      if (delegate && nfsrv_issuedelegs &&
                          writedeleg && !NFSVNO_EXRDONLY(exp) &&
                          (nfsrv_writedelegifpos || !readonly) &&
                          (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) ==
                           LCL_CALLBACKSON &&
                          !NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt) &&
                          NFSVNO_DELEGOK(vp)) {
                          new_deleg->ls_stateid.seqid = delegstateidp->seqid = 0;
                          new_deleg->ls_stateid.other[0] = delegstateidp->other[0]
                              = clp->lc_clientid.lval[0];
                          new_deleg->ls_stateid.other[1] = delegstateidp->other[1]
                              = clp->lc_clientid.lval[1];
                          new_deleg->ls_stateid.other[2] = delegstateidp->other[2]
                              = nfsrv_nextstateindex(clp);
                          new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                              NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                          *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                          new_deleg->ls_uid = new_stp->ls_uid;
                          new_deleg->ls_lfp = lfp;
                          new_deleg->ls_clp = clp;
                          new_deleg->ls_filerev = filerev;
                          new_deleg->ls_compref = nd->nd_compref;
                          LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                          LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                              new_deleg->ls_stateid), new_deleg, ls_hash);
                          LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                          new_deleg = NULL;
                          newnfsstats.srvdelegates++;
                          nfsrv_openpluslock++;
                          nfsrv_delegatecnt++;
                      }
                  } else {
                      new_open->ls_stateid.seqid = 0;
                      new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                      new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                      new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                      new_open->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS)|
                          NFSLCK_OPEN;
                      new_open->ls_uid = new_stp->ls_uid;
                      new_open->ls_openowner = ownerstp;
                      new_open->ls_lfp = lfp;
                      new_open->ls_clp = clp;
                      LIST_INIT(&new_open->ls_open);
                      LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                      LIST_INSERT_HEAD(&ownerstp->ls_open, new_open, ls_list);
                      LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                          new_open, ls_hash);
                      openstp = new_open;
                      new_open = NULL;
                      newnfsstats.srvopens++;
                      nfsrv_openpluslock++;
  
                      /*
                       * This is where we can choose to issue a delegation.
                       */
                      if (delegate && nfsrv_issuedelegs &&
                          (writedeleg || readonly) &&
                          (clp->lc_flags & (LCL_CALLBACKSON | LCL_CBDOWN)) ==
                           LCL_CALLBACKSON &&
                          !NFSRV_V4DELEGLIMIT(nfsrv_delegatecnt) &&
                          NFSVNO_DELEGOK(vp)) {
                          new_deleg->ls_stateid.seqid = delegstateidp->seqid = 0;
                          new_deleg->ls_stateid.other[0] = delegstateidp->other[0]
                              = clp->lc_clientid.lval[0];
                          new_deleg->ls_stateid.other[1] = delegstateidp->other[1]
                              = clp->lc_clientid.lval[1];
                          new_deleg->ls_stateid.other[2] = delegstateidp->other[2]
                              = nfsrv_nextstateindex(clp);
                          if (writedeleg && !NFSVNO_EXRDONLY(exp) &&
                              (nfsrv_writedelegifpos || !readonly)) {
                              new_deleg->ls_flags = (NFSLCK_DELEGWRITE |
                                  NFSLCK_READACCESS | NFSLCK_WRITEACCESS);
                              *rflagsp |= NFSV4OPEN_WRITEDELEGATE;
                          } else {
                              new_deleg->ls_flags = (NFSLCK_DELEGREAD |
                                  NFSLCK_READACCESS);
                              *rflagsp |= NFSV4OPEN_READDELEGATE;
                          }
                          new_deleg->ls_uid = new_stp->ls_uid;
                          new_deleg->ls_lfp = lfp;
                          new_deleg->ls_clp = clp;
                          new_deleg->ls_filerev = filerev;
                          new_deleg->ls_compref = nd->nd_compref;
                          LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file);
                          LIST_INSERT_HEAD(NFSSTATEHASH(clp,
                              new_deleg->ls_stateid), new_deleg, ls_hash);
                          LIST_INSERT_HEAD(&clp->lc_deleg, new_deleg, ls_list);
                          new_deleg = NULL;
                          newnfsstats.srvdelegates++;
                          nfsrv_openpluslock++;
                          nfsrv_delegatecnt++;
                      }
                  }
          } else {
                  /*
                   * New owner case. Start the open_owner sequence with a
                   * Needs confirmation (unless a reclaim) and hang the
                   * new open off it.
                   */
                  new_open->ls_stateid.seqid = 0;
                  new_open->ls_stateid.other[0] = clp->lc_clientid.lval[0];
                  new_open->ls_stateid.other[1] = clp->lc_clientid.lval[1];
                  new_open->ls_stateid.other[2] = nfsrv_nextstateindex(clp);
                  new_open->ls_flags = (new_stp->ls_flags & NFSLCK_SHAREBITS) |
                      NFSLCK_OPEN;
                  new_open->ls_uid = new_stp->ls_uid;
                  LIST_INIT(&new_open->ls_open);
                  new_open->ls_openowner = new_stp;
                  new_open->ls_lfp = lfp;
                  new_open->ls_clp = clp;
                  LIST_INSERT_HEAD(&lfp->lf_open, new_open, ls_file);
                  if (new_stp->ls_flags & NFSLCK_RECLAIM) {
                          new_stp->ls_flags = 0;
                  } else {
                          *rflagsp |= NFSV4OPEN_RESULTCONFIRM;
                          new_stp->ls_flags = NFSLCK_NEEDSCONFIRM;
                  }
                  nfsrvd_refcache(new_stp->ls_op);
                  new_stp->ls_noopens = 0;
                  LIST_INIT(&new_stp->ls_open);
                  LIST_INSERT_HEAD(&new_stp->ls_open, new_open, ls_list);
                  LIST_INSERT_HEAD(&clp->lc_open, new_stp, ls_list);
                  LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_open->ls_stateid),
                      new_open, ls_hash);
                  openstp = new_open;
                  new_open = NULL;
                  *new_stpp = NULL;
                  newnfsstats.srvopens++;
                  nfsrv_openpluslock++;
                  newnfsstats.srvopenowners++;
                  nfsrv_openpluslock++;
          }
          if (!error) {
                  stateidp->seqid = openstp->ls_stateid.seqid;
                  stateidp->other[0] = openstp->ls_stateid.other[0];
                  stateidp->other[1] = openstp->ls_stateid.other[1];
                  stateidp->other[2] = openstp->ls_stateid.other[2];
          }
          NFSUNLOCKSTATE();
          if (haslock) {
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                  NFSUNLOCKV4ROOTMUTEX();
          }
          if (new_open)
                  FREE((caddr_t)new_open, M_NFSDSTATE);
          if (new_deleg)
                  FREE((caddr_t)new_deleg, M_NFSDSTATE);
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Open update. Does the confirm, downgrade and close.
   */
  APPLESTATIC int
  nfsrv_openupdate(vnode_t vp, struct nfsstate *new_stp, nfsquad_t clientid,
      nfsv4stateid_t *stateidp, struct nfsrv_descript *nd, NFSPROC_T *p)
  {
          struct nfsstate *stp, *ownerstp;
          struct nfsclient *clp;
          struct nfslockfile *lfp;
          u_int32_t bits;
          int error = 0, gotstate = 0, len = 0;
          u_char client[NFSV4_OPAQUELIMIT];
  
          /*
           * Check for restart conditions (client and server).
           */
          error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
              &new_stp->ls_stateid, 0);
          if (error)
                  goto out;
  
          NFSLOCKSTATE();
          /*
           * Get the open structure via clientid and stateid.
           */
          error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
              (nfsquad_t)((u_quad_t)0), NULL, p);
          if (!error)
                  error = nfsrv_getstate(clp, &new_stp->ls_stateid,
                      new_stp->ls_flags, &stp);
  
          /*
           * Sanity check the open.
           */
          if (!error && (!(stp->ls_flags & NFSLCK_OPEN) ||
                  (!(new_stp->ls_flags & NFSLCK_CONFIRM) &&
                   (stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM)) ||
                  ((new_stp->ls_flags & NFSLCK_CONFIRM) &&
                   (!(stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM)))))
                  error = NFSERR_BADSTATEID;
  
          if (!error)
                  error = nfsrv_checkseqid(nd, new_stp->ls_seq,
                      stp->ls_openowner, new_stp->ls_op);
          if (!error && stp->ls_stateid.seqid != new_stp->ls_stateid.seqid &&
              !(new_stp->ls_flags & NFSLCK_CONFIRM))
                  error = NFSERR_OLDSTATEID;
          if (!error && vnode_vtype(vp) != VREG) {
                  if (vnode_vtype(vp) == VDIR)
                          error = NFSERR_ISDIR;
                  else
                          error = NFSERR_INVAL;
          }
  
          if (error) {
                  /*
                   * If a client tries to confirm an Open with a bad
                   * seqid# and there are no byte range locks or other Opens
                   * on the openowner, just throw it away, so the next use of the
                   * openowner will start a fresh seq#.
                   */
                  if (error == NFSERR_BADSEQID &&
                      (new_stp->ls_flags & NFSLCK_CONFIRM) &&
                      nfsrv_nootherstate(stp))
                          nfsrv_freeopenowner(stp->ls_openowner, 0, p);
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * Set the return stateid.
           */
          stateidp->seqid = stp->ls_stateid.seqid + 1;
          stateidp->other[0] = stp->ls_stateid.other[0];
          stateidp->other[1] = stp->ls_stateid.other[1];
          stateidp->other[2] = stp->ls_stateid.other[2];
          /*
           * Now, handle the three cases.
           */
          if (new_stp->ls_flags & NFSLCK_CONFIRM) {
                  /*
                   * If the open doesn't need confirmation, it seems to me that
                   * there is a client error, but I'll just log it and keep going?
                   */
                  if (!(stp->ls_openowner->ls_flags & NFSLCK_NEEDSCONFIRM))
                          printf("Nfsv4d: stray open confirm\n");
                  stp->ls_openowner->ls_flags = 0;
                  stp->ls_stateid.seqid++;
                  if (!(clp->lc_flags & LCL_STAMPEDSTABLE)) {
                          clp->lc_flags |= LCL_STAMPEDSTABLE;
                          len = clp->lc_idlen;
                          NFSBCOPY(clp->lc_id, client, len);
                          gotstate = 1;
                  }
                  NFSUNLOCKSTATE();
          } else if (new_stp->ls_flags & NFSLCK_CLOSE) {
                  ownerstp = stp->ls_openowner;
                  lfp = stp->ls_lfp;
                  if (nfsrv_dolocallocks != 0 && !LIST_EMPTY(&stp->ls_open)) {
                          /* Get the lf lock */
                          nfsrv_locklf(lfp);
                          NFSUNLOCKSTATE();
                          if (nfsrv_freeopen(stp, vp, 1, p) == 0) {
                                  NFSLOCKSTATE();
                                  nfsrv_unlocklf(lfp);
                                  NFSUNLOCKSTATE();
                          }
                  } else {
                          (void) nfsrv_freeopen(stp, NULL, 0, p);
                          NFSUNLOCKSTATE();
                  }
          } else {
                  /*
                   * Update the share bits, making sure that the new set are a
                   * subset of the old ones.
                   */
                  bits = (new_stp->ls_flags & NFSLCK_SHAREBITS);
                  if (~(stp->ls_flags) & bits) {
                          NFSUNLOCKSTATE();
                          error = NFSERR_INVAL;
                          goto out;
                  }
                  stp->ls_flags = (bits | NFSLCK_OPEN);
                  stp->ls_stateid.seqid++;
                  NFSUNLOCKSTATE();
          }
  
          /*
           * If the client just confirmed its first open, write a timestamp
           * to the stable storage file.
           */
          if (gotstate != 0) {
                  nfsrv_writestable(client, len, NFSNST_NEWSTATE, p);
                  nfsrv_backupstable();
          }
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Delegation update. Does the purge and return.
   */
  APPLESTATIC int
  nfsrv_delegupdate(nfsquad_t clientid, nfsv4stateid_t *stateidp,
      vnode_t vp, int op, struct ucred *cred, NFSPROC_T *p)
  {
          struct nfsstate *stp;
          struct nfsclient *clp;
          int error = 0;
          fhandle_t fh;
  
          /*
           * Do a sanity check against the file handle for DelegReturn.
           */
          if (vp) {
                  error = nfsvno_getfh(vp, &fh, p);
                  if (error)
                          goto out;
          }
          /*
           * Check for restart conditions (client and server).
           */
          if (op == NFSV4OP_DELEGRETURN)
                  error = nfsrv_checkrestart(clientid, NFSLCK_DELEGRETURN,
                          stateidp, 0);
          else
                  error = nfsrv_checkrestart(clientid, NFSLCK_DELEGPURGE,
                          stateidp, 0);
  
          NFSLOCKSTATE();
          /*
           * Get the open structure via clientid and stateid.
           */
          if (!error)
              error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
                  (nfsquad_t)((u_quad_t)0), NULL, p);
          if (error) {
                  if (error == NFSERR_CBPATHDOWN)
                          error = 0;
                  if (error == NFSERR_STALECLIENTID && op == NFSV4OP_DELEGRETURN)
                          error = NFSERR_STALESTATEID;
          }
          if (!error && op == NFSV4OP_DELEGRETURN) {
              error = nfsrv_getstate(clp, stateidp, NFSLCK_DELEGRETURN, &stp);
              if (!error && stp->ls_stateid.seqid != stateidp->seqid)
                  error = NFSERR_OLDSTATEID;
          }
          /*
           * NFSERR_EXPIRED means that the state has gone away,
           * so Delegations have been purged. Just return ok.
           */
          if (error == NFSERR_EXPIRED && op == NFSV4OP_DELEGPURGE) {
                  NFSUNLOCKSTATE();
                  error = 0;
                  goto out;
          }
          if (error) {
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          if (op == NFSV4OP_DELEGRETURN) {
                  if (NFSBCMP((caddr_t)&fh, (caddr_t)&stp->ls_lfp->lf_fh,
                      sizeof (fhandle_t))) {
                          NFSUNLOCKSTATE();
                          error = NFSERR_BADSTATEID;
                          goto out;
                  }
                  nfsrv_freedeleg(stp);
          } else {
                  nfsrv_freedeleglist(&clp->lc_olddeleg);
          }
          NFSUNLOCKSTATE();
          error = 0;
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Release lock owner.
   */
  APPLESTATIC int
  nfsrv_releaselckown(struct nfsstate *new_stp, nfsquad_t clientid,
      NFSPROC_T *p)
  {
          struct nfsstate *stp, *nstp, *openstp, *ownstp;
          struct nfsclient *clp;
          int error = 0;
  
          /*
           * Check for restart conditions (client and server).
           */
          error = nfsrv_checkrestart(clientid, new_stp->ls_flags,
              &new_stp->ls_stateid, 0);
          if (error)
                  goto out;
  
          NFSLOCKSTATE();
          /*
           * Get the lock owner by name.
           */
          error = nfsrv_getclient(clientid, CLOPS_RENEW, &clp,
              (nfsquad_t)((u_quad_t)0), NULL, p);
          if (error) {
                  NFSUNLOCKSTATE();
                  goto out;
          }
          LIST_FOREACH(ownstp, &clp->lc_open, ls_list) {
              LIST_FOREACH(openstp, &ownstp->ls_open, ls_list) {
                  stp = LIST_FIRST(&openstp->ls_open);
                  while (stp != LIST_END(&openstp->ls_open)) {
                      nstp = LIST_NEXT(stp, ls_list);
                      /*
                       * If the owner matches, check for locks and
                       * then free or return an error.
                       */
                      if (stp->ls_ownerlen == new_stp->ls_ownerlen &&
                          !NFSBCMP(stp->ls_owner, new_stp->ls_owner,
                           stp->ls_ownerlen)){
                          if (LIST_EMPTY(&stp->ls_lock)) {
                              nfsrv_freelockowner(stp, NULL, 0, p);
                          } else {
                              NFSUNLOCKSTATE();
                              error = NFSERR_LOCKSHELD;
                              goto out;
                          }
                      }
                      stp = nstp;
                  }
              }
          }
          NFSUNLOCKSTATE();
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Get the file handle for a lock structure.
   */
  static int
  nfsrv_getlockfh(vnode_t vp, u_short flags,
      struct nfslockfile **new_lfpp, fhandle_t *nfhp, NFSPROC_T *p)
  {
          fhandle_t *fhp = NULL;
          struct nfslockfile *new_lfp;
          int error;
  
          /*
           * For lock, use the new nfslock structure, otherwise just
           * a fhandle_t on the stack.
           */
          if (flags & NFSLCK_OPEN) {
                  new_lfp = *new_lfpp;
                  fhp = &new_lfp->lf_fh;
          } else if (nfhp) {
                  fhp = nfhp;
          } else {
                  panic("nfsrv_getlockfh");
          }
          error = nfsvno_getfh(vp, fhp, p);
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Get an nfs lock structure. Allocate one, as required, and return a
   * pointer to it.
   * Returns an NFSERR_xxx upon failure or -1 to indicate no current lock.
   */
  static int
  nfsrv_getlockfile(u_short flags, struct nfslockfile **new_lfpp,
      struct nfslockfile **lfpp, fhandle_t *nfhp, int lockit)
  {
          struct nfslockfile *lfp;
          fhandle_t *fhp = NULL, *tfhp;
          struct nfslockhashhead *hp;
          struct nfslockfile *new_lfp = NULL;
  
          /*
           * For lock, use the new nfslock structure, otherwise just
           * a fhandle_t on the stack.
           */
          if (flags & NFSLCK_OPEN) {
                  new_lfp = *new_lfpp;
                  fhp = &new_lfp->lf_fh;
          } else if (nfhp) {
                  fhp = nfhp;
          } else {
                  panic("nfsrv_getlockfile");
          }
  
          hp = NFSLOCKHASH(fhp);
          LIST_FOREACH(lfp, hp, lf_hash) {
                  tfhp = &lfp->lf_fh;
                  if (NFSVNO_CMPFH(fhp, tfhp)) {
                          if (lockit)
                                  nfsrv_locklf(lfp);
                          *lfpp = lfp;
                          return (0);
                  }
          }
          if (!(flags & NFSLCK_OPEN))
                  return (-1);
  
          /*
           * No match, so chain the new one into the list.
           */
          LIST_INIT(&new_lfp->lf_open);
          LIST_INIT(&new_lfp->lf_lock);
          LIST_INIT(&new_lfp->lf_deleg);
          LIST_INIT(&new_lfp->lf_locallock);
          LIST_INIT(&new_lfp->lf_rollback);
          new_lfp->lf_locallock_lck.nfslock_usecnt = 0;
          new_lfp->lf_locallock_lck.nfslock_lock = 0;
          new_lfp->lf_usecount = 0;
          LIST_INSERT_HEAD(hp, new_lfp, lf_hash);
          *lfpp = new_lfp;
          *new_lfpp = NULL;
          return (0);
  }
  
  /*
   * This function adds a nfslock lock structure to the list for the associated
   * nfsstate and nfslockfile structures. It will be inserted after the
   * entry pointed at by insert_lop.
   */
  static void
  nfsrv_insertlock(struct nfslock *new_lop, struct nfslock *insert_lop,
      struct nfsstate *stp, struct nfslockfile *lfp)
  {
          struct nfslock *lop, *nlop;
  
          new_lop->lo_stp = stp;
          new_lop->lo_lfp = lfp;
  
          if (stp != NULL) {
                  /* Insert in increasing lo_first order */
                  lop = LIST_FIRST(&lfp->lf_lock);
                  if (lop == LIST_END(&lfp->lf_lock) ||
                      new_lop->lo_first <= lop->lo_first) {
                          LIST_INSERT_HEAD(&lfp->lf_lock, new_lop, lo_lckfile);
                  } else {
                          nlop = LIST_NEXT(lop, lo_lckfile);
                          while (nlop != LIST_END(&lfp->lf_lock) &&
                                 nlop->lo_first < new_lop->lo_first) {
                                  lop = nlop;
                                  nlop = LIST_NEXT(lop, lo_lckfile);
                          }
                          LIST_INSERT_AFTER(lop, new_lop, lo_lckfile);
                  }
          } else {
                  new_lop->lo_lckfile.le_prev = NULL;     /* list not used */
          }
  
          /*
           * Insert after insert_lop, which is overloaded as stp or lfp for
           * an empty list.
           */
          if (stp == NULL && (struct nfslockfile *)insert_lop == lfp)
                  LIST_INSERT_HEAD(&lfp->lf_locallock, new_lop, lo_lckowner);
          else if ((struct nfsstate *)insert_lop == stp)
                  LIST_INSERT_HEAD(&stp->ls_lock, new_lop, lo_lckowner);
          else
                  LIST_INSERT_AFTER(insert_lop, new_lop, lo_lckowner);
          if (stp != NULL) {
                  newnfsstats.srvlocks++;
                  nfsrv_openpluslock++;
          }
  }
  
  /*
   * This function updates the locking for a lock owner and given file. It
   * maintains a list of lock ranges ordered on increasing file offset that
   * are NFSLCK_READ or NFSLCK_WRITE and non-overlapping (aka POSIX style).
   * It always adds new_lop to the list and sometimes uses the one pointed
   * at by other_lopp.
   */
  static void
  nfsrv_updatelock(struct nfsstate *stp, struct nfslock **new_lopp,
      struct nfslock **other_lopp, struct nfslockfile *lfp)
  {
          struct nfslock *new_lop = *new_lopp;
          struct nfslock *lop, *tlop, *ilop;
          struct nfslock *other_lop = *other_lopp;
          int unlock = 0, myfile = 0;
          u_int64_t tmp;
  
          /*
           * Work down the list until the lock is merged.
           */
          if (new_lop->lo_flags & NFSLCK_UNLOCK)
                  unlock = 1;
          if (stp != NULL) {
                  ilop = (struct nfslock *)stp;
                  lop = LIST_FIRST(&stp->ls_lock);
          } else {
                  ilop = (struct nfslock *)lfp;
                  lop = LIST_FIRST(&lfp->lf_locallock);
          }
          while (lop != NULL) {
              /*
               * Only check locks for this file that aren't before the start of
               * new lock's range.
               */
              if (lop->lo_lfp == lfp) {
                myfile = 1;
                if (lop->lo_end >= new_lop->lo_first) {
                  if (new_lop->lo_end < lop->lo_first) {
                          /*
                           * If the new lock ends before the start of the
                           * current lock's range, no merge, just insert
                           * the new lock.
                           */
                          break;
                  }
                  if (new_lop->lo_flags == lop->lo_flags ||
                      (new_lop->lo_first <= lop->lo_first &&
                       new_lop->lo_end >= lop->lo_end)) {
                          /*
                           * This lock can be absorbed by the new lock/unlock.
                           * This happens when it covers the entire range
                           * of the old lock or is contiguous
                           * with the old lock and is of the same type or an
                           * unlock.
                           */
                          if (lop->lo_first < new_lop->lo_first)
                                  new_lop->lo_first = lop->lo_first;
                          if (lop->lo_end > new_lop->lo_end)
                                  new_lop->lo_end = lop->lo_end;
                          tlop = lop;
                          lop = LIST_NEXT(lop, lo_lckowner);
                          nfsrv_freenfslock(tlop);
                          continue;
                  }
  
                  /*
                   * All these cases are for contiguous locks that are not the
                   * same type, so they can't be merged.
                   */
                  if (new_lop->lo_first <= lop->lo_first) {
                          /*
                           * This case is where the new lock overlaps with the
                           * first part of the old lock. Move the start of the
                           * old lock to just past the end of the new lock. The
                           * new lock will be inserted in front of the old, since
                           * ilop hasn't been updated. (We are done now.)
                           */
                          lop->lo_first = new_lop->lo_end;
                          break;
                  }
                  if (new_lop->lo_end >= lop->lo_end) {
                          /*
                           * This case is where the new lock overlaps with the
                           * end of the old lock's range. Move the old lock's
                           * end to just before the new lock's first and insert
                           * the new lock after the old lock.
                           * Might not be done yet, since the new lock could
                           * overlap further locks with higher ranges.
                           */
                          lop->lo_end = new_lop->lo_first;
                          ilop = lop;
                          lop = LIST_NEXT(lop, lo_lckowner);
                          continue;
                  }
                  /*
                   * The final case is where the new lock's range is in the
                   * middle of the current lock's and splits the current lock
                   * up. Use *other_lopp to handle the second part of the
                   * split old lock range. (We are done now.)
                   * For unlock, we use new_lop as other_lop and tmp, since
                   * other_lop and new_lop are the same for this case.
                   * We noted the unlock case above, so we don't need
                   * new_lop->lo_flags any longer.
                   */
                  tmp = new_lop->lo_first;
                  if (other_lop == NULL) {
                          if (!unlock)
                                  panic("nfsd srv update unlock");
                          other_lop = new_lop;
                          *new_lopp = NULL;
                  }
                  other_lop->lo_first = new_lop->lo_end;
                  other_lop->lo_end = lop->lo_end;
                  other_lop->lo_flags = lop->lo_flags;
                  other_lop->lo_stp = stp;
                  other_lop->lo_lfp = lfp;
                  lop->lo_end = tmp;
                  nfsrv_insertlock(other_lop, lop, stp, lfp);
                  *other_lopp = NULL;
                  ilop = lop;
                  break;
                }
              }
              ilop = lop;
              lop = LIST_NEXT(lop, lo_lckowner);
              if (myfile && (lop == NULL || lop->lo_lfp != lfp))
                  break;
          }
  
          /*
           * Insert the new lock in the list at the appropriate place.
           */
          if (!unlock) {
                  nfsrv_insertlock(new_lop, ilop, stp, lfp);
                  *new_lopp = NULL;
          }
  }
  
  /*
   * This function handles sequencing of locks, etc.
   * It returns an error that indicates what the caller should do.
   */
  static int
  nfsrv_checkseqid(struct nfsrv_descript *nd, u_int32_t seqid,
      struct nfsstate *stp, struct nfsrvcache *op)
  {
          int error = 0;
  
          if (op != nd->nd_rp)
                  panic("nfsrvstate checkseqid");
          if (!(op->rc_flag & RC_INPROG))
                  panic("nfsrvstate not inprog");
          if (stp->ls_op && stp->ls_op->rc_refcnt <= 0) {
                  printf("refcnt=%d\n", stp->ls_op->rc_refcnt);
                  panic("nfsrvstate op refcnt");
          }
          if ((stp->ls_seq + 1) == seqid) {
                  if (stp->ls_op)
                          nfsrvd_derefcache(stp->ls_op);
                  stp->ls_op = op;
                  nfsrvd_refcache(op);
                  stp->ls_seq = seqid;
                  goto out;
          } else if (stp->ls_seq == seqid && stp->ls_op &&
                  op->rc_xid == stp->ls_op->rc_xid &&
                  op->rc_refcnt == 0 &&
                  op->rc_reqlen == stp->ls_op->rc_reqlen &&
                  op->rc_cksum == stp->ls_op->rc_cksum) {
                  if (stp->ls_op->rc_flag & RC_INPROG) {
                          error = NFSERR_DONTREPLY;
                          goto out;
                  }
                  nd->nd_rp = stp->ls_op;
                  nd->nd_rp->rc_flag |= RC_INPROG;
                  nfsrvd_delcache(op);
                  error = NFSERR_REPLYFROMCACHE;
                  goto out;
          }
          error = NFSERR_BADSEQID;
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Get the client ip address for callbacks. If the strings can't be parsed,
   * just set lc_program to 0 to indicate no callbacks are possible.
   * (For cases where the address can't be parsed or is 0.0.0.0.0.0, set
   *  the address to the client's transport address. This won't be used
   *  for callbacks, but can be printed out by newnfsstats for info.)
   * Return error if the xdr can't be parsed, 0 otherwise.
   */
  APPLESTATIC int
  nfsrv_getclientipaddr(struct nfsrv_descript *nd, struct nfsclient *clp)
  {
          u_int32_t *tl;
          u_char *cp, *cp2;
          int i, j;
          struct sockaddr_in *rad, *sad;
          u_char protocol[5], addr[24];
          int error = 0, cantparse = 0;
          union {
                  u_long ival;
                  u_char cval[4];
          } ip;
          union {
                  u_short sval;
                  u_char cval[2];
          } port;
  
          rad = NFSSOCKADDR(clp->lc_req.nr_nam, struct sockaddr_in *);
          rad->sin_family = AF_INET;
          rad->sin_len = sizeof (struct sockaddr_in);
          rad->sin_addr.s_addr = 0;
          rad->sin_port = 0;
          clp->lc_req.nr_client = NULL;
          clp->lc_req.nr_lock = 0;
          NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
          i = fxdr_unsigned(int, *tl);
          if (i >= 3 && i <= 4) {
                  error = nfsrv_mtostr(nd, protocol, i);
                  if (error)
                          goto nfsmout;
                  if (!strcmp(protocol, "tcp")) {
                          clp->lc_flags |= LCL_TCPCALLBACK;
                          clp->lc_req.nr_sotype = SOCK_STREAM;
                          clp->lc_req.nr_soproto = IPPROTO_TCP;
                  } else if (!strcmp(protocol, "udp")) {
                          clp->lc_req.nr_sotype = SOCK_DGRAM;
                          clp->lc_req.nr_soproto = IPPROTO_UDP;
                  } else {
                          cantparse = 1;
                  }
          } else {
                  cantparse = 1;
                  if (i > 0) {
                          error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                          if (error)
                                  goto nfsmout;
                  }
          }
          NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
          i = fxdr_unsigned(int, *tl);
          if (i < 0) {
                  error = NFSERR_BADXDR;
                  goto nfsmout;
          } else if (i == 0) {
                  cantparse = 1;
          } else if (!cantparse && i <= 23 && i >= 11) {
                  error = nfsrv_mtostr(nd, addr, i);
                  if (error)
                          goto nfsmout;
  
                  /*
                   * Parse out the address fields. We expect 6 decimal numbers
                   * separated by '.'s.
                   */
                  cp = addr;
                  i = 0;
                  while (*cp && i < 6) {
                          cp2 = cp;
                          while (*cp2 && *cp2 != '.')
                                  cp2++;
                          if (*cp2)
                                  *cp2++ = '\0';
                          else if (i != 5) {
                                  cantparse = 1;
                                  break;
                          }
                          j = nfsrv_getipnumber(cp);
                          if (j >= 0) {
                                  if (i < 4)
                                          ip.cval[3 - i] = j;
                                  else
                                          port.cval[5 - i] = j;
                          } else {
                                  cantparse = 1;
                                  break;
                          }
                          cp = cp2;
                          i++;
                  }
                  if (!cantparse) {
                          if (ip.ival != 0x0) {
                                  rad->sin_addr.s_addr = htonl(ip.ival);
                                  rad->sin_port = htons(port.sval);
                          } else {
                                  cantparse = 1;
                          }
                  }
          } else {
                  cantparse = 1;
                  if (i > 0) {
                          error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                          if (error)
                                  goto nfsmout;
                  }
          }
          if (cantparse) {
                  sad = NFSSOCKADDR(nd->nd_nam, struct sockaddr_in *);
                  rad->sin_addr.s_addr = sad->sin_addr.s_addr;
                  rad->sin_port = 0x0;
                  clp->lc_program = 0;
          }
  nfsmout:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Turn a string of up to three decimal digits into a number. Return -1 upon
   * error.
   */
  static int
  nfsrv_getipnumber(u_char *cp)
  {
          int i = 0, j = 0;
  
          while (*cp) {
                  if (j > 2 || *cp < '' || *cp > '9')
                          return (-1);
                  i *= 10;
                  i += (*cp - '');
                  cp++;
                  j++;
          }
          if (i < 256)
                  return (i);
          return (-1);
  }
  
  /*
   * This function checks for restart conditions.
   */
  static int
  nfsrv_checkrestart(nfsquad_t clientid, u_int32_t flags,
      nfsv4stateid_t *stateidp, int specialid)
  {
          int ret = 0;
  
          /*
           * First check for a server restart. Open, LockT, ReleaseLockOwner
           * and DelegPurge have a clientid, the rest a stateid.
           */
          if (flags &
              (NFSLCK_OPEN | NFSLCK_TEST | NFSLCK_RELEASE | NFSLCK_DELEGPURGE)) {
                  if (clientid.lval[0] != nfsrvboottime) {
                          ret = NFSERR_STALECLIENTID;
                          goto out;
                  }
          } else if (stateidp->other[0] != nfsrvboottime &&
                  specialid == 0) {
                  ret = NFSERR_STALESTATEID;
                  goto out;
          }
  
          /*
           * Read, Write, Setattr and LockT can return NFSERR_GRACE and do
           * not use a lock/open owner seqid#, so the check can be done now.
           * (The others will be checked, as required, later.)
           */
          if (!(flags & (NFSLCK_CHECK | NFSLCK_TEST)))
                  goto out;
  
          NFSLOCKSTATE();
          ret = nfsrv_checkgrace(flags);
          NFSUNLOCKSTATE();
  
  out:
          NFSEXITCODE(ret);
          return (ret);
  }
  
  /*
   * Check for grace.
   */
  static int
  nfsrv_checkgrace(u_int32_t flags)
  {
          int error = 0;
  
          if (nfsrv_stablefirst.nsf_flags & NFSNSF_GRACEOVER) {
                  if (flags & NFSLCK_RECLAIM) {
                          error = NFSERR_NOGRACE;
                          goto out;
                  }
          } else {
                  if (!(flags & NFSLCK_RECLAIM)) {
                          error = NFSERR_GRACE;
                          goto out;
                  }
  
                  /*
                   * If grace is almost over and we are still getting Reclaims,
                   * extend grace a bit.
                   */
                  if ((NFSD_MONOSEC + NFSRV_LEASEDELTA) >
                      nfsrv_stablefirst.nsf_eograce)
                          nfsrv_stablefirst.nsf_eograce = NFSD_MONOSEC +
                                  NFSRV_LEASEDELTA;
          }
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Do a server callback.
   */
  static int
  nfsrv_docallback(struct nfsclient *clp, int procnum,
      nfsv4stateid_t *stateidp, int trunc, fhandle_t *fhp,
      struct nfsvattr *nap, nfsattrbit_t *attrbitp, NFSPROC_T *p)
  {
          mbuf_t m;
          u_int32_t *tl;
          struct nfsrv_descript nfsd, *nd = &nfsd;
          struct ucred *cred;
          int error = 0;
          u_int32_t callback;
  
          cred = newnfs_getcred();
          NFSLOCKSTATE(); /* mostly for lc_cbref++ */
          if (clp->lc_flags & LCL_NEEDSCONFIRM) {
                  NFSUNLOCKSTATE();
                  panic("docallb");
          }
          clp->lc_cbref++;
  
          /*
           * Fill the callback program# and version into the request
           * structure for newnfs_connect() to use.
           */
          clp->lc_req.nr_prog = clp->lc_program;
          clp->lc_req.nr_vers = NFSV4_CBVERS;
  
          /*
           * First, fill in some of the fields of nd and cr.
           */
          nd->nd_flag = ND_NFSV4;
          if (clp->lc_flags & LCL_GSS)
                  nd->nd_flag |= ND_KERBV;
          nd->nd_repstat = 0;
          cred->cr_uid = clp->lc_uid;
          cred->cr_gid = clp->lc_gid;
          callback = clp->lc_callback;
          NFSUNLOCKSTATE();
          cred->cr_ngroups = 1;
  
          /*
           * Get the first mbuf for the request.
           */
          MGET(m, M_WAITOK, MT_DATA);
          mbuf_setlen(m, 0);
          nd->nd_mreq = nd->nd_mb = m;
          nd->nd_bpos = NFSMTOD(m, caddr_t);
          
          /*
           * and build the callback request.
           */
          if (procnum == NFSV4OP_CBGETATTR) {
                  nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
                  (void) nfsm_strtom(nd, "CB Getattr", 10);
                  NFSM_BUILD(tl, u_int32_t *, 4 * NFSX_UNSIGNED);
                  *tl++ = txdr_unsigned(NFSV4_MINORVERSION);
                  *tl++ = txdr_unsigned(callback);
                  *tl++ = txdr_unsigned(1);
                  *tl = txdr_unsigned(NFSV4OP_CBGETATTR);
                  (void) nfsm_fhtom(nd, (u_int8_t *)fhp, NFSX_MYFH, 0);
                  (void) nfsrv_putattrbit(nd, attrbitp);
          } else if (procnum == NFSV4OP_CBRECALL) {
                  nd->nd_procnum = NFSV4PROC_CBCOMPOUND;
                  (void) nfsm_strtom(nd, "CB Recall", 9);
                  NFSM_BUILD(tl, u_int32_t *, 5 * NFSX_UNSIGNED + NFSX_STATEID);
                  *tl++ = txdr_unsigned(NFSV4_MINORVERSION);
                  *tl++ = txdr_unsigned(callback);
                  *tl++ = txdr_unsigned(1);
                  *tl++ = txdr_unsigned(NFSV4OP_CBRECALL);
                  *tl++ = txdr_unsigned(stateidp->seqid);
                  NFSBCOPY((caddr_t)stateidp->other, (caddr_t)tl,
                      NFSX_STATEIDOTHER);
                  tl += (NFSX_STATEIDOTHER / NFSX_UNSIGNED);
                  if (trunc)
                          *tl = newnfs_true;
                  else
                          *tl = newnfs_false;
                  (void) nfsm_fhtom(nd, (u_int8_t *)fhp, NFSX_MYFH, 0);
          } else {
                  nd->nd_procnum = NFSV4PROC_CBNULL;
          }
  
          /*
           * Call newnfs_connect(), as required, and then newnfs_request().
           */
          (void) newnfs_sndlock(&clp->lc_req.nr_lock);
          if (clp->lc_req.nr_client == NULL) {
                  if (nd->nd_procnum == NFSV4PROC_CBNULL)
                          error = newnfs_connect(NULL, &clp->lc_req, cred,
                              NULL, 1);
                  else
                          error = newnfs_connect(NULL, &clp->lc_req, cred,
                              NULL, 3);
          }
          newnfs_sndunlock(&clp->lc_req.nr_lock);
          if (!error) {
                  error = newnfs_request(nd, NULL, clp, &clp->lc_req, NULL,
                      NULL, cred, clp->lc_program, NFSV4_CBVERS, NULL, 1, NULL,
                      NULL);
          }
          NFSFREECRED(cred);
  
          /*
           * If error is set here, the Callback path isn't working
           * properly, so twiddle the appropriate LCL_ flags.
           * (nd_repstat != 0 indicates the Callback path is working,
           *  but the callback failed on the client.)
           */
          if (error) {
                  /*
                   * Mark the callback pathway down, which disabled issuing
                   * of delegations and gets Renew to return NFSERR_CBPATHDOWN.
                   */
                  NFSLOCKSTATE();
                  clp->lc_flags |= LCL_CBDOWN;
                  NFSUNLOCKSTATE();
          } else {
                  /*
                   * Callback worked. If the callback path was down, disable
                   * callbacks, so no more delegations will be issued. (This
                   * is done on the assumption that the callback pathway is
                   * flakey.)
                   */
                  NFSLOCKSTATE();
                  if (clp->lc_flags & LCL_CBDOWN)
                          clp->lc_flags &= ~(LCL_CBDOWN | LCL_CALLBACKSON);
                  NFSUNLOCKSTATE();
                  if (nd->nd_repstat)
                          error = nd->nd_repstat;
                  else if (procnum == NFSV4OP_CBGETATTR)
                          error = nfsv4_loadattr(nd, NULL, nap, NULL, NULL, 0,
                              NULL, NULL, NULL, NULL, NULL, 0, NULL, NULL, NULL,
                              p, NULL);
                  mbuf_freem(nd->nd_mrep);
          }
          NFSLOCKSTATE();
          clp->lc_cbref--;
          if ((clp->lc_flags & LCL_WAKEUPWANTED) && clp->lc_cbref == 0) {
                  clp->lc_flags &= ~LCL_WAKEUPWANTED;
                  wakeup(clp);
          }
          NFSUNLOCKSTATE();
  
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Return the next index# for a clientid. Mostly just increment and return
   * the next one, but... if the 32bit unsigned does actually wrap around,
   * it should be rebooted.
   * At an average rate of one new client per second, it will wrap around in
   * approximately 136 years. (I think the server will have been shut
   * down or rebooted before then.)
   */
  static u_int32_t
  nfsrv_nextclientindex(void)
  {
          static u_int32_t client_index = 0;
  
          client_index++;
          if (client_index != 0)
                  return (client_index);
  
          printf("%s: out of clientids\n", __func__);
          return (client_index);
  }
  
  /*
   * Return the next index# for a stateid. Mostly just increment and return
   * the next one, but... if the 32bit unsigned does actually wrap around
   * (will a BSD server stay up that long?), find
   * new start and end values.
   */
  static u_int32_t
  nfsrv_nextstateindex(struct nfsclient *clp)
  {
          struct nfsstate *stp;
          int i;
          u_int32_t canuse, min_index, max_index;
  
          if (!(clp->lc_flags & LCL_INDEXNOTOK)) {
                  clp->lc_stateindex++;
                  if (clp->lc_stateindex != clp->lc_statemaxindex)
                          return (clp->lc_stateindex);
          }
  
          /*
           * Yuck, we've hit the end.
           * Look for a new min and max.
           */
          min_index = 0;
          max_index = 0xffffffff;
          for (i = 0; i < NFSSTATEHASHSIZE; i++) {
              LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                  if (stp->ls_stateid.other[2] > 0x80000000) {
                      if (stp->ls_stateid.other[2] < max_index)
                          max_index = stp->ls_stateid.other[2];
                  } else {
                      if (stp->ls_stateid.other[2] > min_index)
                          min_index = stp->ls_stateid.other[2];
                  }
              }
          }
  
          /*
           * Yikes, highly unlikely, but I'll handle it anyhow.
           */
          if (min_index == 0x80000000 && max_index == 0x80000001) {
              canuse = 0;
              /*
               * Loop around until we find an unused entry. Return that
               * and set LCL_INDEXNOTOK, so the search will continue next time.
               * (This is one of those rare cases where a goto is the
               *  cleanest way to code the loop.)
               */
  tryagain:
              for (i = 0; i < NFSSTATEHASHSIZE; i++) {
                  LIST_FOREACH(stp, &clp->lc_stateid[i], ls_hash) {
                      if (stp->ls_stateid.other[2] == canuse) {
                          canuse++;
                          goto tryagain;
                      }
                  }
              }
              clp->lc_flags |= LCL_INDEXNOTOK;
              return (canuse);
          }
  
          /*
           * Ok to start again from min + 1.
           */
          clp->lc_stateindex = min_index + 1;
          clp->lc_statemaxindex = max_index;
          clp->lc_flags &= ~LCL_INDEXNOTOK;
          return (clp->lc_stateindex);
  }
  
  /*
   * The following functions handle the stable storage file that deals with
   * the edge conditions described in RFC3530 Sec. 8.6.3.
   * The file is as follows:
   * - a single record at the beginning that has the lease time of the
   *   previous server instance (before the last reboot) and the nfsrvboottime
   *   values for the previous server boots.
   *   These previous boot times are used to ensure that the current
   *   nfsrvboottime does not, somehow, get set to a previous one.
   *   (This is important so that Stale ClientIDs and StateIDs can
   *    be recognized.)
   *   The number of previous nfsvrboottime values preceeds the list.
   * - followed by some number of appended records with:
   *   - client id string
   *   - flag that indicates it is a record revoking state via lease
   *     expiration or similar
   *     OR has successfully acquired state.
   * These structures vary in length, with the client string at the end, up
   * to NFSV4_OPAQUELIMIT in size.
   *
   * At the end of the grace period, the file is truncated, the first
   * record is rewritten with updated information and any acquired state
   * records for successful reclaims of state are written.
   *
   * Subsequent records are appended when the first state is issued to
   * a client and when state is revoked for a client.
   *
   * When reading the file in, state issued records that come later in
   * the file override older ones, since the append log is in cronological order.
   * If, for some reason, the file can't be read, the grace period is
   * immediately terminated and all reclaims get NFSERR_NOGRACE.
   */
  
  /*
   * Read in the stable storage file. Called by nfssvc() before the nfsd
   * processes start servicing requests.
   */
  APPLESTATIC void
  nfsrv_setupstable(NFSPROC_T *p)
  {
          struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
          struct nfsrv_stable *sp, *nsp;
          struct nfst_rec *tsp;
          int error, i, tryagain;
          off_t off = 0;
          ssize_t aresid, len;
  
          /*
           * If NFSNSF_UPDATEDONE is set, this is a restart of the nfsds without
           * a reboot, so state has not been lost.
           */
          if (sf->nsf_flags & NFSNSF_UPDATEDONE)
                  return;
          /*
           * Set Grace over just until the file reads successfully.
           */
          nfsrvboottime = time_second;
          LIST_INIT(&sf->nsf_head);
          sf->nsf_flags = (NFSNSF_GRACEOVER | NFSNSF_NEEDLOCK);
          sf->nsf_eograce = NFSD_MONOSEC + NFSRV_LEASEDELTA;
          if (sf->nsf_fp == NULL)
                  return;
          error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
              (caddr_t)&sf->nsf_rec, sizeof (struct nfsf_rec), off, UIO_SYSSPACE,
              0, NFSFPCRED(sf->nsf_fp), &aresid, p);
          if (error || aresid || sf->nsf_numboots == 0 ||
                  sf->nsf_numboots > NFSNSF_MAXNUMBOOTS)
                  return;
  
          /*
           * Now, read in the boottimes.
           */
          sf->nsf_bootvals = (time_t *)malloc((sf->nsf_numboots + 1) *
                  sizeof (time_t), M_TEMP, M_WAITOK);
          off = sizeof (struct nfsf_rec);
          error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
              (caddr_t)sf->nsf_bootvals, sf->nsf_numboots * sizeof (time_t), off,
              UIO_SYSSPACE, 0, NFSFPCRED(sf->nsf_fp), &aresid, p);
          if (error || aresid) {
                  free((caddr_t)sf->nsf_bootvals, M_TEMP);
                  sf->nsf_bootvals = NULL;
                  return;
          }
  
          /*
           * Make sure this nfsrvboottime is different from all recorded
           * previous ones.
           */
          do {
                  tryagain = 0;
                  for (i = 0; i < sf->nsf_numboots; i++) {
                          if (nfsrvboottime == sf->nsf_bootvals[i]) {
                                  nfsrvboottime++;
                                  tryagain = 1;
                                  break;
                          }
                  }
          } while (tryagain);
  
          sf->nsf_flags |= NFSNSF_OK;
          off += (sf->nsf_numboots * sizeof (time_t));
  
          /*
           * Read through the file, building a list of records for grace
           * checking.
           * Each record is between sizeof (struct nfst_rec) and
           * sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1
           * and is actually sizeof (struct nfst_rec) + nst_len - 1.
           */
          tsp = (struct nfst_rec *)malloc(sizeof (struct nfst_rec) +
                  NFSV4_OPAQUELIMIT - 1, M_TEMP, M_WAITOK);
          do {
              error = NFSD_RDWR(UIO_READ, NFSFPVNODE(sf->nsf_fp),
                  (caddr_t)tsp, sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1,
                  off, UIO_SYSSPACE, 0, NFSFPCRED(sf->nsf_fp), &aresid, p);
              len = (sizeof (struct nfst_rec) + NFSV4_OPAQUELIMIT - 1) - aresid;
              if (error || (len > 0 && (len < sizeof (struct nfst_rec) ||
                  len < (sizeof (struct nfst_rec) + tsp->len - 1)))) {
                  /*
                   * Yuck, the file has been corrupted, so just return
                   * after clearing out any restart state, so the grace period
                   * is over.
                   */
                  LIST_FOREACH_SAFE(sp, &sf->nsf_head, nst_list, nsp) {
                          LIST_REMOVE(sp, nst_list);
                          free((caddr_t)sp, M_TEMP);
                  }
                  free((caddr_t)tsp, M_TEMP);
                  sf->nsf_flags &= ~NFSNSF_OK;
                  free((caddr_t)sf->nsf_bootvals, M_TEMP);
                  sf->nsf_bootvals = NULL;
                  return;
              }
              if (len > 0) {
                  off += sizeof (struct nfst_rec) + tsp->len - 1;
                  /*
                   * Search the list for a matching client.
                   */
                  LIST_FOREACH(sp, &sf->nsf_head, nst_list) {
                          if (tsp->len == sp->nst_len &&
                              !NFSBCMP(tsp->client, sp->nst_client, tsp->len))
                                  break;
                  }
                  if (sp == LIST_END(&sf->nsf_head)) {
                          sp = (struct nfsrv_stable *)malloc(tsp->len +
                                  sizeof (struct nfsrv_stable) - 1, M_TEMP,
                                  M_WAITOK);
                          NFSBCOPY((caddr_t)tsp, (caddr_t)&sp->nst_rec,
                                  sizeof (struct nfst_rec) + tsp->len - 1);
                          LIST_INSERT_HEAD(&sf->nsf_head, sp, nst_list);
                  } else {
                          if (tsp->flag == NFSNST_REVOKE)
                                  sp->nst_flag |= NFSNST_REVOKE;
                          else
                                  /*
                                   * A subsequent timestamp indicates the client
                                   * did a setclientid/confirm and any previous
                                   * revoke is no longer relevant.
                                   */
                                  sp->nst_flag &= ~NFSNST_REVOKE;
                  }
              }
          } while (len > 0);
          free((caddr_t)tsp, M_TEMP);
          sf->nsf_flags = NFSNSF_OK;
          sf->nsf_eograce = NFSD_MONOSEC + sf->nsf_lease +
                  NFSRV_LEASEDELTA;
  }
  
  /*
   * Update the stable storage file, now that the grace period is over.
   */
  APPLESTATIC void
  nfsrv_updatestable(NFSPROC_T *p)
  {
          struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
          struct nfsrv_stable *sp, *nsp;
          int i;
          struct nfsvattr nva;
          vnode_t vp;
  #if defined(__FreeBSD_version) && (__FreeBSD_version >= 500000)
          mount_t mp = NULL;
  #endif
          int error;
  
          if (sf->nsf_fp == NULL || (sf->nsf_flags & NFSNSF_UPDATEDONE))
                  return;
          sf->nsf_flags |= NFSNSF_UPDATEDONE;
          /*
           * Ok, we need to rewrite the stable storage file.
           * - truncate to 0 length
           * - write the new first structure
           * - loop through the data structures, writing out any that
           *   have timestamps older than the old boot
           */
          if (sf->nsf_bootvals) {
                  sf->nsf_numboots++;
                  for (i = sf->nsf_numboots - 2; i >= 0; i--)
                          sf->nsf_bootvals[i + 1] = sf->nsf_bootvals[i];
          } else {
                  sf->nsf_numboots = 1;
                  sf->nsf_bootvals = (time_t *)malloc(sizeof (time_t),
                          M_TEMP, M_WAITOK);
          }
          sf->nsf_bootvals[0] = nfsrvboottime;
          sf->nsf_lease = nfsrv_lease;
          NFSVNO_ATTRINIT(&nva);
          NFSVNO_SETATTRVAL(&nva, size, 0);
          vp = NFSFPVNODE(sf->nsf_fp);
          vn_start_write(vp, &mp, V_WAIT);
          if (NFSVOPLOCK(vp, LK_EXCLUSIVE) == 0) {
                  error = nfsvno_setattr(vp, &nva, NFSFPCRED(sf->nsf_fp), p,
                      NULL);
                  NFSVOPUNLOCK(vp, 0);
          } else
                  error = EPERM;
          vn_finished_write(mp);
          if (!error)
              error = NFSD_RDWR(UIO_WRITE, vp,
                  (caddr_t)&sf->nsf_rec, sizeof (struct nfsf_rec), (off_t)0,
                  UIO_SYSSPACE, IO_SYNC, NFSFPCRED(sf->nsf_fp), NULL, p);
          if (!error)
              error = NFSD_RDWR(UIO_WRITE, vp,
                  (caddr_t)sf->nsf_bootvals,
                  sf->nsf_numboots * sizeof (time_t),
                  (off_t)(sizeof (struct nfsf_rec)),
                  UIO_SYSSPACE, IO_SYNC, NFSFPCRED(sf->nsf_fp), NULL, p);
          free((caddr_t)sf->nsf_bootvals, M_TEMP);
          sf->nsf_bootvals = NULL;
          if (error) {
                  sf->nsf_flags &= ~NFSNSF_OK;
                  printf("EEK! Can't write NfsV4 stable storage file\n");
                  return;
          }
          sf->nsf_flags |= NFSNSF_OK;
  
          /*
           * Loop through the list and write out timestamp records for
           * any clients that successfully reclaimed state.
           */
          LIST_FOREACH_SAFE(sp, &sf->nsf_head, nst_list, nsp) {
                  if (sp->nst_flag & NFSNST_GOTSTATE) {
                          nfsrv_writestable(sp->nst_client, sp->nst_len,
                                  NFSNST_NEWSTATE, p);
                          sp->nst_clp->lc_flags |= LCL_STAMPEDSTABLE;
                  }
                  LIST_REMOVE(sp, nst_list);
                  free((caddr_t)sp, M_TEMP);
          }
          nfsrv_backupstable();
  }
  
  /*
   * Append a record to the stable storage file.
   */
  APPLESTATIC void
  nfsrv_writestable(u_char *client, int len, int flag, NFSPROC_T *p)
  {
          struct nfsrv_stablefirst *sf = &nfsrv_stablefirst;
          struct nfst_rec *sp;
          int error;
  
          if (!(sf->nsf_flags & NFSNSF_OK) || sf->nsf_fp == NULL)
                  return;
          sp = (struct nfst_rec *)malloc(sizeof (struct nfst_rec) +
                  len - 1, M_TEMP, M_WAITOK);
          sp->len = len;
          NFSBCOPY(client, sp->client, len);
          sp->flag = flag;
          error = NFSD_RDWR(UIO_WRITE, NFSFPVNODE(sf->nsf_fp),
              (caddr_t)sp, sizeof (struct nfst_rec) + len - 1, (off_t)0,
              UIO_SYSSPACE, (IO_SYNC | IO_APPEND), NFSFPCRED(sf->nsf_fp), NULL, p);
          free((caddr_t)sp, M_TEMP);
          if (error) {
                  sf->nsf_flags &= ~NFSNSF_OK;
                  printf("EEK! Can't write NfsV4 stable storage file\n");
          }
  }
  
  /*
   * This function is called during the grace period to mark a client
   * that successfully reclaimed state.
   */
  static void
  nfsrv_markstable(struct nfsclient *clp)
  {
          struct nfsrv_stable *sp;
  
          /*
           * First find the client structure.
           */
          LIST_FOREACH(sp, &nfsrv_stablefirst.nsf_head, nst_list) {
                  if (sp->nst_len == clp->lc_idlen &&
                      !NFSBCMP(sp->nst_client, clp->lc_id, sp->nst_len))
                          break;
          }
          if (sp == LIST_END(&nfsrv_stablefirst.nsf_head))
                  return;
  
          /*
           * Now, just mark it and set the nfsclient back pointer.
           */
          sp->nst_flag |= NFSNST_GOTSTATE;
          sp->nst_clp = clp;
  }
  
  /*
   * This function is called for a reclaim, to see if it gets grace.
   * It returns 0 if a reclaim is allowed, 1 otherwise.
   */
  static int
  nfsrv_checkstable(struct nfsclient *clp)
  {
          struct nfsrv_stable *sp;
  
          /*
           * First, find the entry for the client.
           */
          LIST_FOREACH(sp, &nfsrv_stablefirst.nsf_head, nst_list) {
                  if (sp->nst_len == clp->lc_idlen &&
                      !NFSBCMP(sp->nst_client, clp->lc_id, sp->nst_len))
                          break;
          }
  
          /*
           * If not in the list, state was revoked or no state was issued
           * since the previous reboot, a reclaim is denied.
           */
          if (sp == LIST_END(&nfsrv_stablefirst.nsf_head) ||
              (sp->nst_flag & NFSNST_REVOKE) ||
              !(nfsrv_stablefirst.nsf_flags & NFSNSF_OK))
                  return (1);
          return (0);
  }
  
  /*
   * Test for and try to clear out a conflicting client. This is called by
   * nfsrv_lockctrl() and nfsrv_openctrl() when conflicts with other clients
   * a found.
   * The trick here is that it can't revoke a conflicting client with an
   * expired lease unless it holds the v4root lock, so...
   * If no v4root lock, get the lock and return 1 to indicate "try again".
   * Return 0 to indicate the conflict can't be revoked and 1 to indicate
   * the revocation worked and the conflicting client is "bye, bye", so it
   * can be tried again.
   * Return 2 to indicate that the vnode is VI_DOOMED after NFSVOPLOCK().
   * Unlocks State before a non-zero value is returned.
   */
  static int
  nfsrv_clientconflict(struct nfsclient *clp, int *haslockp, vnode_t vp,
      NFSPROC_T *p)
  {
          int gotlock, lktype;
  
          /*
           * If lease hasn't expired, we can't fix it.
           */
          if (clp->lc_expiry >= NFSD_MONOSEC ||
              !(nfsrv_stablefirst.nsf_flags & NFSNSF_UPDATEDONE))
                  return (0);
          if (*haslockp == 0) {
                  NFSUNLOCKSTATE();
                  lktype = NFSVOPISLOCKED(vp);
                  NFSVOPUNLOCK(vp, 0);
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_relref(&nfsv4rootfs_lock);
                  do {
                          gotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                              NFSV4ROOTLOCKMUTEXPTR, NULL);
                  } while (!gotlock);
                  NFSUNLOCKV4ROOTMUTEX();
                  *haslockp = 1;
                  NFSVOPLOCK(vp, lktype | LK_RETRY);
                  if ((vp->v_iflag & VI_DOOMED) != 0)
                          return (2);
                  else
                          return (1);
          }
          NFSUNLOCKSTATE();
  
          /*
           * Ok, we can expire the conflicting client.
           */
          nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
          nfsrv_backupstable();
          nfsrv_cleanclient(clp, p);
          nfsrv_freedeleglist(&clp->lc_deleg);
          nfsrv_freedeleglist(&clp->lc_olddeleg);
          LIST_REMOVE(clp, lc_hash);
          nfsrv_zapclient(clp, p);
          return (1);
  }
  
  /*
   * Resolve a delegation conflict.
   * Returns 0 to indicate the conflict was resolved without sleeping.
   * Return -1 to indicate that the caller should check for conflicts again.
   * Return > 0 for an error that should be returned, normally NFSERR_DELAY.
   *
   * Also, manipulate the nfsv4root_lock, as required. It isn't changed
   * for a return of 0, since there was no sleep and it could be required
   * later. It is released for a return of NFSERR_DELAY, since the caller
   * will return that error. It is released when a sleep was done waiting
   * for the delegation to be returned or expire (so that other nfsds can
   * handle ops). Then, it must be acquired for the write to stable storage.
   * (This function is somewhat similar to nfsrv_clientconflict(), but
   *  the semantics differ in a couple of subtle ways. The return of 0
   *  indicates the conflict was resolved without sleeping here, not
   *  that the conflict can't be resolved and the handling of nfsv4root_lock
   *  differs, as noted above.)
   * Unlocks State before returning a non-zero value.
   */
  static int
  nfsrv_delegconflict(struct nfsstate *stp, int *haslockp, NFSPROC_T *p,
      vnode_t vp)
  {
          struct nfsclient *clp = stp->ls_clp;
          int gotlock, error, lktype, retrycnt, zapped_clp;
          nfsv4stateid_t tstateid;
          fhandle_t tfh;
  
          /*
           * If the conflict is with an old delegation...
           */
          if (stp->ls_flags & NFSLCK_OLDDELEG) {
                  /*
                   * You can delete it, if it has expired.
                   */
                  if (clp->lc_delegtime < NFSD_MONOSEC) {
                          nfsrv_freedeleg(stp);
                          NFSUNLOCKSTATE();
                          error = -1;
                          goto out;
                  }
                  NFSUNLOCKSTATE();
                  /*
                   * During this delay, the old delegation could expire or it
                   * could be recovered by the client via an Open with
                   * CLAIM_DELEGATE_PREV.
                   * Release the nfsv4root_lock, if held.
                   */
                  if (*haslockp) {
                          *haslockp = 0;
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  error = NFSERR_DELAY;
                  goto out;
          }
  
          /*
           * It's a current delegation, so:
           * - check to see if the delegation has expired
           *   - if so, get the v4root lock and then expire it
           */
          if (!(stp->ls_flags & NFSLCK_DELEGRECALL)) {
                  /*
                   * - do a recall callback, since not yet done
                   * For now, never allow truncate to be set. To use
                   * truncate safely, it must be guaranteed that the
                   * Remove, Rename or Setattr with size of 0 will
                   * succeed and that would require major changes to
                   * the VFS/Vnode OPs.
                   * Set the expiry time large enough so that it won't expire
                   * until after the callback, then set it correctly, once
                   * the callback is done. (The delegation will now time
                   * out whether or not the Recall worked ok. The timeout
                   * will be extended when ops are done on the delegation
                   * stateid, up to the timelimit.)
                   */
                  stp->ls_delegtime = NFSD_MONOSEC + (2 * nfsrv_lease) +
                      NFSRV_LEASEDELTA;
                  stp->ls_delegtimelimit = NFSD_MONOSEC + (6 * nfsrv_lease) +
                      NFSRV_LEASEDELTA;
                  stp->ls_flags |= NFSLCK_DELEGRECALL;
  
                  /*
                   * Loop NFSRV_CBRETRYCNT times while the CBRecall replies
                   * NFSERR_BADSTATEID or NFSERR_BADHANDLE. This is done
                   * in order to try and avoid a race that could happen
                   * when a CBRecall request passed the Open reply with
                   * the delegation in it when transitting the network.
                   * Since nfsrv_docallback will sleep, don't use stp after
                   * the call.
                   */
                  NFSBCOPY((caddr_t)&stp->ls_stateid, (caddr_t)&tstateid,
                      sizeof (tstateid));
                  NFSBCOPY((caddr_t)&stp->ls_lfp->lf_fh, (caddr_t)&tfh,
                      sizeof (tfh));
                  NFSUNLOCKSTATE();
                  if (*haslockp) {
                          *haslockp = 0;
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  retrycnt = 0;
                  do {
                      error = nfsrv_docallback(clp, NFSV4OP_CBRECALL,
                          &tstateid, 0, &tfh, NULL, NULL, p);
                      retrycnt++;
                  } while ((error == NFSERR_BADSTATEID ||
                      error == NFSERR_BADHANDLE) && retrycnt < NFSV4_CBRETRYCNT);
                  error = NFSERR_DELAY;
                  goto out;
          }
  
          if (clp->lc_expiry >= NFSD_MONOSEC &&
              stp->ls_delegtime >= NFSD_MONOSEC) {
                  NFSUNLOCKSTATE();
                  /*
                   * A recall has been done, but it has not yet expired.
                   * So, RETURN_DELAY.
                   */
                  if (*haslockp) {
                          *haslockp = 0;
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  error = NFSERR_DELAY;
                  goto out;
          }
  
          /*
           * If we don't yet have the lock, just get it and then return,
           * since we need that before deleting expired state, such as
           * this delegation.
           * When getting the lock, unlock the vnode, so other nfsds that
           * are in progress, won't get stuck waiting for the vnode lock.
           */
          if (*haslockp == 0) {
                  NFSUNLOCKSTATE();
                  lktype = NFSVOPISLOCKED(vp);
                  NFSVOPUNLOCK(vp, 0);
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_relref(&nfsv4rootfs_lock);
                  do {
                          gotlock = nfsv4_lock(&nfsv4rootfs_lock, 1, NULL,
                              NFSV4ROOTLOCKMUTEXPTR, NULL);
                  } while (!gotlock);
                  NFSUNLOCKV4ROOTMUTEX();
                  *haslockp = 1;
                  NFSVOPLOCK(vp, lktype | LK_RETRY);
                  if ((vp->v_iflag & VI_DOOMED) != 0) {
                          *haslockp = 0;
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                          error = NFSERR_PERM;
                          goto out;
                  }
                  error = -1;
                  goto out;
          }
  
          NFSUNLOCKSTATE();
          /*
           * Ok, we can delete the expired delegation.
           * First, write the Revoke record to stable storage and then
           * clear out the conflict.
           * Since all other nfsd threads are now blocked, we can safely
           * sleep without the state changing.
           */
          nfsrv_writestable(clp->lc_id, clp->lc_idlen, NFSNST_REVOKE, p);
          nfsrv_backupstable();
          if (clp->lc_expiry < NFSD_MONOSEC) {
                  nfsrv_cleanclient(clp, p);
                  nfsrv_freedeleglist(&clp->lc_deleg);
                  nfsrv_freedeleglist(&clp->lc_olddeleg);
                  LIST_REMOVE(clp, lc_hash);
                  zapped_clp = 1;
          } else {
                  nfsrv_freedeleg(stp);
                  zapped_clp = 0;
          }
          if (zapped_clp)
                  nfsrv_zapclient(clp, p);
          error = -1;
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Check for a remove allowed, if remove is set to 1 and get rid of
   * delegations.
   */
  APPLESTATIC int
  nfsrv_checkremove(vnode_t vp, int remove, NFSPROC_T *p)
  {
          struct nfsstate *stp;
          struct nfslockfile *lfp;
          int error, haslock = 0;
          fhandle_t nfh;
  
          /*
           * First, get the lock file structure.
           * (A return of -1 means no associated state, so remove ok.)
           */
          error = nfsrv_getlockfh(vp, NFSLCK_CHECK, NULL, &nfh, p);
  tryagain:
          NFSLOCKSTATE();
          if (!error)
                  error = nfsrv_getlockfile(NFSLCK_CHECK, NULL, &lfp, &nfh, 0);
          if (error) {
                  NFSUNLOCKSTATE();
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  if (error == -1)
                          error = 0;
                  goto out;
          }
  
          /*
           * Now, we must Recall any delegations.
           */
          error = nfsrv_cleandeleg(vp, lfp, NULL, &haslock, p);
          if (error) {
                  /*
                   * nfsrv_cleandeleg() unlocks state for non-zero
                   * return.
                   */
                  if (error == -1)
                          goto tryagain;
                  if (haslock) {
                          NFSLOCKV4ROOTMUTEX();
                          nfsv4_unlock(&nfsv4rootfs_lock, 1);
                          NFSUNLOCKV4ROOTMUTEX();
                  }
                  goto out;
          }
  
          /*
           * Now, look for a conflicting open share.
           */
          if (remove) {
                  LIST_FOREACH(stp, &lfp->lf_open, ls_file) {
                          if (stp->ls_flags & NFSLCK_WRITEDENY) {
                                  error = NFSERR_FILEOPEN;
                                  break;
                          }
                  }
          }
  
          NFSUNLOCKSTATE();
          if (haslock) {
                  NFSLOCKV4ROOTMUTEX();
                  nfsv4_unlock(&nfsv4rootfs_lock, 1);
                  NFSUNLOCKV4ROOTMUTEX();
          }
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Clear out all delegations for the file referred to by lfp.
   * May return NFSERR_DELAY, if there will be a delay waiting for
   * delegations to expire.
   * Returns -1 to indicate it slept while recalling a delegation.
   * This function has the side effect of deleting the nfslockfile structure,
   * if it no longer has associated state and didn't have to sleep.
   * Unlocks State before a non-zero value is returned.
   */
  static int
  nfsrv_cleandeleg(vnode_t vp, struct nfslockfile *lfp,
      struct nfsclient *clp, int *haslockp, NFSPROC_T *p)
  {
          struct nfsstate *stp, *nstp;
          int ret = 0;
  
          stp = LIST_FIRST(&lfp->lf_deleg);
          while (stp != LIST_END(&lfp->lf_deleg)) {
                  nstp = LIST_NEXT(stp, ls_file);
                  if (stp->ls_clp != clp) {
                          ret = nfsrv_delegconflict(stp, haslockp, p, vp);
                          if (ret) {
                                  /*
                                   * nfsrv_delegconflict() unlocks state
                                   * when it returns non-zero.
                                   */
                                  goto out;
                          }
                  }
                  stp = nstp;
          }
  out:
          NFSEXITCODE(ret);
          return (ret);
  }
  
  /*
   * There are certain operations that, when being done outside of NFSv4,
   * require that any NFSv4 delegation for the file be recalled.
   * This function is to be called for those cases:
   * VOP_RENAME() - When a delegation is being recalled for any reason,
   *      the client may have to do Opens against the server, using the file's
   *      final component name. If the file has been renamed on the server,
   *      that component name will be incorrect and the Open will fail.
   * VOP_REMOVE() - Theoretically, a client could Open a file after it has
   *      been removed on the server, if there is a delegation issued to
   *      that client for the file. I say "theoretically" since clients
   *      normally do an Access Op before the Open and that Access Op will
   *      fail with ESTALE. Note that NFSv2 and 3 don't even do Opens, so
   *      they will detect the file's removal in the same manner. (There is
   *      one case where RFC3530 allows a client to do an Open without first
   *      doing an Access Op, which is passage of a check against the ACE
   *      returned with a Write delegation, but current practice is to ignore
   *      the ACE and always do an Access Op.)
   *      Since the functions can only be called with an unlocked vnode, this
   *      can't be done at this time.
   * VOP_ADVLOCK() - When a client holds a delegation, it can issue byte range
   *      locks locally in the client, which are not visible to the server. To
   *      deal with this, issuing of delegations for a vnode must be disabled
   *      and all delegations for the vnode recalled. This is done via the
   *      second function, using the VV_DISABLEDELEG vflag on the vnode.
   */
  APPLESTATIC void
  nfsd_recalldelegation(vnode_t vp, NFSPROC_T *p)
  {
          time_t starttime;
          int error;
  
          /*
           * First, check to see if the server is currently running and it has
           * been called for a regular file when issuing delegations.
           */
          if (newnfs_numnfsd == 0 || vp->v_type != VREG ||
              nfsrv_issuedelegs == 0)
                  return;
  
          KASSERT((NFSVOPISLOCKED(vp) != LK_EXCLUSIVE), ("vp %p is locked", vp));
          /*
           * First, get a reference on the nfsv4rootfs_lock so that an
           * exclusive lock cannot be acquired by another thread.
           */
          NFSLOCKV4ROOTMUTEX();
          nfsv4_getref(&nfsv4rootfs_lock, NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
          NFSUNLOCKV4ROOTMUTEX();
  
          /*
           * Now, call nfsrv_checkremove() in a loop while it returns
           * NFSERR_DELAY. Return upon any other error or when timed out.
           */
          starttime = NFSD_MONOSEC;
          do {
                  if (NFSVOPLOCK(vp, LK_EXCLUSIVE) == 0) {
                          error = nfsrv_checkremove(vp, 0, p);
                          NFSVOPUNLOCK(vp, 0);
                  } else
                          error = EPERM;
                  if (error == NFSERR_DELAY) {
                          if (NFSD_MONOSEC - starttime > NFS_REMOVETIMEO)
                                  break;
                          /* Sleep for a short period of time */
                          (void) nfs_catnap(PZERO, 0, "nfsremove");
                  }
          } while (error == NFSERR_DELAY);
          NFSLOCKV4ROOTMUTEX();
          nfsv4_relref(&nfsv4rootfs_lock);
          NFSUNLOCKV4ROOTMUTEX();
  }
  
  APPLESTATIC void
  nfsd_disabledelegation(vnode_t vp, NFSPROC_T *p)
  {
  
  #ifdef VV_DISABLEDELEG
          /*
           * First, flag issuance of delegations disabled.
           */
          atomic_set_long(&vp->v_vflag, VV_DISABLEDELEG);
  #endif
  
          /*
           * Then call nfsd_recalldelegation() to get rid of all extant
           * delegations.
           */
          nfsd_recalldelegation(vp, p);
  }
  
  /*
   * Check for conflicting locks, etc. and then get rid of delegations.
   * (At one point I thought that I should get rid of delegations for any
   *  Setattr, since it could potentially disallow the I/O op (read or write)
   *  allowed by the delegation. However, Setattr Ops that aren't changing
   *  the size get a stateid of all 0s, so you can't tell if it is a delegation
   *  for the same client or a different one, so I decided to only get rid
   *  of delegations for other clients when the size is being changed.)
   * In general, a Setattr can disable NFS I/O Ops that are outstanding, such
   * as Write backs, even if there is no delegation, so it really isn't any
   * different?)
   */
  APPLESTATIC int
  nfsrv_checksetattr(vnode_t vp, struct nfsrv_descript *nd,
      nfsv4stateid_t *stateidp, struct nfsvattr *nvap, nfsattrbit_t *attrbitp,
      struct nfsexstuff *exp, NFSPROC_T *p)
  {
          struct nfsstate st, *stp = &st;
          struct nfslock lo, *lop = &lo;
          int error = 0;
          nfsquad_t clientid;
  
          if (NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_SIZE)) {
                  stp->ls_flags = (NFSLCK_CHECK | NFSLCK_WRITEACCESS);
                  lop->lo_first = nvap->na_size;
          } else {
                  stp->ls_flags = 0;
                  lop->lo_first = 0;
          }
          if (NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_OWNER) ||
              NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_OWNERGROUP) ||
              NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_MODE) ||
              NFSISSET_ATTRBIT(attrbitp, NFSATTRBIT_ACL))
                  stp->ls_flags |= NFSLCK_SETATTR;
          if (stp->ls_flags == 0)
                  goto out;
          lop->lo_end = NFS64BITSSET;
          lop->lo_flags = NFSLCK_WRITE;
          stp->ls_ownerlen = 0;
          stp->ls_op = NULL;
          stp->ls_uid = nd->nd_cred->cr_uid;
          stp->ls_stateid.seqid = stateidp->seqid;
          clientid.lval[0] = stp->ls_stateid.other[0] = stateidp->other[0];
          clientid.lval[1] = stp->ls_stateid.other[1] = stateidp->other[1];
          stp->ls_stateid.other[2] = stateidp->other[2];
          error = nfsrv_lockctrl(vp, &stp, &lop, NULL, clientid,
              stateidp, exp, nd, p);
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * Check for a write delegation and do a CBGETATTR if there is one, updating
   * the attributes, as required.
   * Should I return an error if I can't get the attributes? (For now, I'll
   * just return ok.
   */
  APPLESTATIC int
  nfsrv_checkgetattr(struct nfsrv_descript *nd, vnode_t vp,
      struct nfsvattr *nvap, nfsattrbit_t *attrbitp, struct ucred *cred,
      NFSPROC_T *p)
  {
          struct nfsstate *stp;
          struct nfslockfile *lfp;
          struct nfsclient *clp;
          struct nfsvattr nva;
          fhandle_t nfh;
          int error = 0;
          nfsattrbit_t cbbits;
          u_quad_t delegfilerev;
  
          NFSCBGETATTR_ATTRBIT(attrbitp, &cbbits);
          if (!NFSNONZERO_ATTRBIT(&cbbits))
                  goto out;
  
          /*
           * Get the lock file structure.
           * (A return of -1 means no associated state, so return ok.)
           */
          error = nfsrv_getlockfh(vp, NFSLCK_CHECK, NULL, &nfh, p);
          NFSLOCKSTATE();
          if (!error)
                  error = nfsrv_getlockfile(NFSLCK_CHECK, NULL, &lfp, &nfh, 0);
          if (error) {
                  NFSUNLOCKSTATE();
                  if (error == -1)
                          error = 0;
                  goto out;
          }
  
          /*
           * Now, look for a write delegation.
           */
          LIST_FOREACH(stp, &lfp->lf_deleg, ls_file) {
                  if (stp->ls_flags & NFSLCK_DELEGWRITE)
                          break;
          }
          if (stp == LIST_END(&lfp->lf_deleg)) {
                  NFSUNLOCKSTATE();
                  goto out;
          }
          clp = stp->ls_clp;
          delegfilerev = stp->ls_filerev;
  
          /*
           * If the Write delegation was issued as a part of this Compound RPC
           * or if we have an Implied Clientid (used in a previous Op in this
           * compound) and it is the client the delegation was issued to,
           * just return ok.
           * I also assume that it is from the same client iff the network
           * host IP address is the same as the callback address. (Not
           * exactly correct by the RFC, but avoids a lot of Getattr
           * callbacks.)
           */
          if (nd->nd_compref == stp->ls_compref ||
              ((nd->nd_flag & ND_IMPLIEDCLID) &&
               clp->lc_clientid.qval == nd->nd_clientid.qval) ||
               nfsaddr2_match(clp->lc_req.nr_nam, nd->nd_nam)) {
                  NFSUNLOCKSTATE();
                  goto out;
          }
  
          /*
           * We are now done with the delegation state structure,
           * so the statelock can be released and we can now tsleep().
           */
  
          /*
           * Now, we must do the CB Getattr callback, to see if Change or Size
           * has changed.
           */
          if (clp->lc_expiry >= NFSD_MONOSEC) {
                  NFSUNLOCKSTATE();
                  NFSVNO_ATTRINIT(&nva);
                  nva.na_filerev = NFS64BITSSET;
                  error = nfsrv_docallback(clp, NFSV4OP_CBGETATTR, NULL,
                      0, &nfh, &nva, &cbbits, p);
                  if (!error) {
                          if ((nva.na_filerev != NFS64BITSSET &&
                              nva.na_filerev > delegfilerev) ||
                              (NFSVNO_ISSETSIZE(&nva) &&
                               nva.na_size != nvap->na_size)) {
                                  nfsvno_updfilerev(vp, nvap, cred, p);
                                  if (NFSVNO_ISSETSIZE(&nva))
                                          nvap->na_size = nva.na_size;
                          }
                  }
          } else {
                  NFSUNLOCKSTATE();
          }
          error = 0;
  
  out:
          NFSEXITCODE2(error, nd);
          return (error);
  }
  
  /*
   * This function looks for openowners that haven't had any opens for
   * a while and throws them away. Called by an nfsd when NFSNSF_NOOPENS
   * is set.
   */
  APPLESTATIC void
  nfsrv_throwawayopens(NFSPROC_T *p)
  {
          struct nfsclient *clp, *nclp;
          struct nfsstate *stp, *nstp;
          int i;
  
          NFSLOCKSTATE();
          nfsrv_stablefirst.nsf_flags &= ~NFSNSF_NOOPENS;
          /*
           * For each client...
           */
          for (i = 0; i < NFSCLIENTHASHSIZE; i++) {
              LIST_FOREACH_SAFE(clp, &nfsclienthash[i], lc_hash, nclp) {
                  LIST_FOREACH_SAFE(stp, &clp->lc_open, ls_list, nstp) {
                          if (LIST_EMPTY(&stp->ls_open) &&
                              (stp->ls_noopens > NFSNOOPEN ||
                               (nfsrv_openpluslock * 2) >
                               NFSRV_V4STATELIMIT))
                                  nfsrv_freeopenowner(stp, 0, p);
                  }
              }
          }
          NFSUNLOCKSTATE();
  }
  
  /*
   * This function checks to see if the credentials are the same.
   * Returns 1 for not same, 0 otherwise.
   */
  static int
  nfsrv_notsamecredname(struct nfsrv_descript *nd, struct nfsclient *clp)
  {
  
          if (nd->nd_flag & ND_GSS) {
                  if (!(clp->lc_flags & LCL_GSS))
                          return (1);
                  if (clp->lc_flags & LCL_NAME) {
                          if (nd->nd_princlen != clp->lc_namelen ||
                              NFSBCMP(nd->nd_principal, clp->lc_name,
                                  clp->lc_namelen))
                                  return (1);
                          else
                                  return (0);
                  }
                  if (nd->nd_cred->cr_uid == clp->lc_uid)
                          return (0);
                  else
                          return (1);
          } else if (clp->lc_flags & LCL_GSS)
                  return (1);
          /*
           * For AUTH_SYS, allow the same uid or root. (This is underspecified
           * in RFC3530, which talks about principals, but doesn't say anything
           * about uids for AUTH_SYS.)
           */
          if (nd->nd_cred->cr_uid == clp->lc_uid || nd->nd_cred->cr_uid == 0)
                  return (0);
          else
                  return (1);
  }
  
  /*
   * Calculate the lease expiry time.
   */
  static time_t
  nfsrv_leaseexpiry(void)
  {
  
          if (nfsrv_stablefirst.nsf_eograce > NFSD_MONOSEC)
                  return (NFSD_MONOSEC + 2 * (nfsrv_lease + NFSRV_LEASEDELTA));
          return (NFSD_MONOSEC + nfsrv_lease + NFSRV_LEASEDELTA);
  }
  
  /*
   * Delay the delegation timeout as far as ls_delegtimelimit, as required.
   */
  static void
  nfsrv_delaydelegtimeout(struct nfsstate *stp)
  {
  
          if ((stp->ls_flags & NFSLCK_DELEGRECALL) == 0)
                  return;
  
          if ((stp->ls_delegtime + 15) > NFSD_MONOSEC &&
              stp->ls_delegtime < stp->ls_delegtimelimit) {
                  stp->ls_delegtime += nfsrv_lease;
                  if (stp->ls_delegtime > stp->ls_delegtimelimit)
                          stp->ls_delegtime = stp->ls_delegtimelimit;
          }
  }
  
  /*
   * This function checks to see if there is any other state associated
   * with the openowner for this Open.
   * It returns 1 if there is no other state, 0 otherwise.
   */
  static int
  nfsrv_nootherstate(struct nfsstate *stp)
  {
          struct nfsstate *tstp;
  
          LIST_FOREACH(tstp, &stp->ls_openowner->ls_open, ls_list) {
                  if (tstp != stp || !LIST_EMPTY(&tstp->ls_lock))
                          return (0);
          }
          return (1);
  }
  
  /*
   * Create a list of lock deltas (changes to local byte range locking
   * that can be rolled back using the list) and apply the changes via
   * nfsvno_advlock(). Optionally, lock the list. It is expected that either
   * the rollback or update function will be called after this.
   * It returns an error (and rolls back, as required), if any nfsvno_advlock()
   * call fails. If it returns an error, it will unlock the list.
   */
  static int
  nfsrv_locallock(vnode_t vp, struct nfslockfile *lfp, int flags,
      uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p)
  {
          struct nfslock *lop, *nlop;
          int error = 0;
  
          /* Loop through the list of locks. */
          lop = LIST_FIRST(&lfp->lf_locallock);
          while (first < end && lop != NULL) {
                  nlop = LIST_NEXT(lop, lo_lckowner);
                  if (first >= lop->lo_end) {
                          /* not there yet */
                          lop = nlop;
                  } else if (first < lop->lo_first) {
                          /* new one starts before entry in list */
                          if (end <= lop->lo_first) {
                                  /* no overlap between old and new */
                                  error = nfsrv_dolocal(vp, lfp, flags,
                                      NFSLCK_UNLOCK, first, end, cfp, p);
                                  if (error != 0)
                                          break;
                                  first = end;
                          } else {
                                  /* handle fragment overlapped with new one */
                                  error = nfsrv_dolocal(vp, lfp, flags,
                                      NFSLCK_UNLOCK, first, lop->lo_first, cfp,
                                      p);
                                  if (error != 0)
                                          break;
                                  first = lop->lo_first;
                          }
                  } else {
                          /* new one overlaps this entry in list */
                          if (end <= lop->lo_end) {
                                  /* overlaps all of new one */
                                  error = nfsrv_dolocal(vp, lfp, flags,
                                      lop->lo_flags, first, end, cfp, p);
                                  if (error != 0)
                                          break;
                                  first = end;
                          } else {
                                  /* handle fragment overlapped with new one */
                                  error = nfsrv_dolocal(vp, lfp, flags,
                                      lop->lo_flags, first, lop->lo_end, cfp, p);
                                  if (error != 0)
                                          break;
                                  first = lop->lo_end;
                                  lop = nlop;
                          }
                  }
          }
          if (first < end && error == 0)
                  /* handle fragment past end of list */
                  error = nfsrv_dolocal(vp, lfp, flags, NFSLCK_UNLOCK, first,
                      end, cfp, p);
  
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Local lock unlock. Unlock all byte ranges that are no longer locked
   * by NFSv4. To do this, unlock any subranges of first-->end that
   * do not overlap with the byte ranges of any lock in the lfp->lf_lock
   * list. This list has all locks for the file held by other
   * <clientid, lockowner> tuples. The list is ordered by increasing
   * lo_first value, but may have entries that overlap each other, for
   * the case of read locks.
   */
  static void
  nfsrv_localunlock(vnode_t vp, struct nfslockfile *lfp, uint64_t init_first,
      uint64_t init_end, NFSPROC_T *p)
  {
          struct nfslock *lop;
          uint64_t first, end, prevfirst;
  
          first = init_first;
          end = init_end;
          while (first < init_end) {
                  /* Loop through all nfs locks, adjusting first and end */
                  prevfirst = 0;
                  LIST_FOREACH(lop, &lfp->lf_lock, lo_lckfile) {
                          KASSERT(prevfirst <= lop->lo_first,
                              ("nfsv4 locks out of order"));
                          KASSERT(lop->lo_first < lop->lo_end,
                              ("nfsv4 bogus lock"));
                          prevfirst = lop->lo_first;
                          if (first >= lop->lo_first &&
                              first < lop->lo_end)
                                  /*
                                   * Overlaps with initial part, so trim
                                   * off that initial part by moving first past
                                   * it.
                                   */
                                  first = lop->lo_end;
                          else if (end > lop->lo_first &&
                              lop->lo_first > first) {
                                  /*
                                   * This lock defines the end of the
                                   * segment to unlock, so set end to the
                                   * start of it and break out of the loop.
                                   */
                                  end = lop->lo_first;
                                  break;
                          }
                          if (first >= end)
                                  /*
                                   * There is no segment left to do, so
                                   * break out of this loop and then exit
                                   * the outer while() since first will be set
                                   * to end, which must equal init_end here.
                                   */
                                  break;
                  }
                  if (first < end) {
                          /* Unlock this segment */
                          (void) nfsrv_dolocal(vp, lfp, NFSLCK_UNLOCK,
                              NFSLCK_READ, first, end, NULL, p);
                          nfsrv_locallock_commit(lfp, NFSLCK_UNLOCK,
                              first, end);
                  }
                  /*
                   * Now move past this segment and look for any further
                   * segment in the range, if there is one.
                   */
                  first = end;
                  end = init_end;
          }
  }
  
  /*
   * Do the local lock operation and update the rollback list, as required.
   * Perform the rollback and return the error if nfsvno_advlock() fails.
   */
  static int
  nfsrv_dolocal(vnode_t vp, struct nfslockfile *lfp, int flags, int oldflags,
      uint64_t first, uint64_t end, struct nfslockconflict *cfp, NFSPROC_T *p)
  {
          struct nfsrollback *rlp;
          int error = 0, ltype, oldltype;
  
          if (flags & NFSLCK_WRITE)
                  ltype = F_WRLCK;
          else if (flags & NFSLCK_READ)
                  ltype = F_RDLCK;
          else
                  ltype = F_UNLCK;
          if (oldflags & NFSLCK_WRITE)
                  oldltype = F_WRLCK;
          else if (oldflags & NFSLCK_READ)
                  oldltype = F_RDLCK;
          else
                  oldltype = F_UNLCK;
          if (ltype == oldltype || (oldltype == F_WRLCK && ltype == F_RDLCK))
                  /* nothing to do */
                  goto out;
          error = nfsvno_advlock(vp, ltype, first, end, p);
          if (error != 0) {
                  if (cfp != NULL) {
                          cfp->cl_clientid.lval[0] = 0;
                          cfp->cl_clientid.lval[1] = 0;
                          cfp->cl_first = 0;
                          cfp->cl_end = NFS64BITSSET;
                          cfp->cl_flags = NFSLCK_WRITE;
                          cfp->cl_ownerlen = 5;
                          NFSBCOPY("LOCAL", cfp->cl_owner, 5);
                  }
                  nfsrv_locallock_rollback(vp, lfp, p);
          } else if (ltype != F_UNLCK) {
                  rlp = malloc(sizeof (struct nfsrollback), M_NFSDROLLBACK,
                      M_WAITOK);
                  rlp->rlck_first = first;
                  rlp->rlck_end = end;
                  rlp->rlck_type = oldltype;
                  LIST_INSERT_HEAD(&lfp->lf_rollback, rlp, rlck_list);
          }
  
  out:
          NFSEXITCODE(error);
          return (error);
  }
  
  /*
   * Roll back local lock changes and free up the rollback list.
   */
  static void
  nfsrv_locallock_rollback(vnode_t vp, struct nfslockfile *lfp, NFSPROC_T *p)
  {
          struct nfsrollback *rlp, *nrlp;
  
          LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list, nrlp) {
                  (void) nfsvno_advlock(vp, rlp->rlck_type, rlp->rlck_first,
                      rlp->rlck_end, p);
                  free(rlp, M_NFSDROLLBACK);
          }
          LIST_INIT(&lfp->lf_rollback);
  }
  
  /*
   * Update local lock list and delete rollback list (ie now committed to the
   * local locks). Most of the work is done by the internal function.
   */
  static void
  nfsrv_locallock_commit(struct nfslockfile *lfp, int flags, uint64_t first,
      uint64_t end)
  {
          struct nfsrollback *rlp, *nrlp;
          struct nfslock *new_lop, *other_lop;
  
          new_lop = malloc(sizeof (struct nfslock), M_NFSDLOCK, M_WAITOK);
          if (flags & (NFSLCK_READ | NFSLCK_WRITE))
                  other_lop = malloc(sizeof (struct nfslock), M_NFSDLOCK,
                      M_WAITOK);
          else
                  other_lop = NULL;
          new_lop->lo_flags = flags;
          new_lop->lo_first = first;
          new_lop->lo_end = end;
          nfsrv_updatelock(NULL, &new_lop, &other_lop, lfp);
          if (new_lop != NULL)
                  free(new_lop, M_NFSDLOCK);
          if (other_lop != NULL)
                  free(other_lop, M_NFSDLOCK);
  
          /* and get rid of the rollback list */
          LIST_FOREACH_SAFE(rlp, &lfp->lf_rollback, rlck_list, nrlp)
                  free(rlp, M_NFSDROLLBACK);
          LIST_INIT(&lfp->lf_rollback);
  }
  
  /*
   * Lock the struct nfslockfile for local lock updating.
   */
  static void
  nfsrv_locklf(struct nfslockfile *lfp)
  {
          int gotlock;
  
          /* lf_usecount ensures *lfp won't be free'd */
          lfp->lf_usecount++;
          do {
                  gotlock = nfsv4_lock(&lfp->lf_locallock_lck, 1, NULL,
                      NFSSTATEMUTEXPTR, NULL);
          } while (gotlock == 0);
          lfp->lf_usecount--;
  }
  
  /*
   * Unlock the struct nfslockfile after local lock updating.
   */
  static void
  nfsrv_unlocklf(struct nfslockfile *lfp)
  {
  
          nfsv4_unlock(&lfp->lf_locallock_lck, 0);
  }
  
  /*
   * Clear out all state for the NFSv4 server.
   * Must be called by a thread that can sleep when no nfsds are running.
   */
  void
  nfsrv_throwawayallstate(NFSPROC_T *p)
  {
          struct nfsclient *clp, *nclp;
          struct nfslockfile *lfp, *nlfp;
          int i;
  
          /*
           * For each client, clean out the state and then free the structure.
           */
          for (i = 0; i < NFSCLIENTHASHSIZE; i++) {
                  LIST_FOREACH_SAFE(clp, &nfsclienthash[i], lc_hash, nclp) {
                          nfsrv_cleanclient(clp, p);
                          nfsrv_freedeleglist(&clp->lc_deleg);
                          nfsrv_freedeleglist(&clp->lc_olddeleg);
                          free(clp, M_NFSDCLIENT);
                  }
          }
  
          /*
           * Also, free up any remaining lock file structures.
           */
          for (i = 0; i < NFSLOCKHASHSIZE; i++) {
                  LIST_FOREACH_SAFE(lfp, &nfslockhash[i], lf_hash, nlfp) {
                          printf("nfsd unload: fnd a lock file struct\n");
                          nfsrv_freenfslockfile(lfp);
                  }
          }
  }